osh mom guidelines on toxic industrial waste treatment

8/13/2019 OSH MOM Guidelines on Toxic Industrial Waste Treatment

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Toxic Industrial Waste

OSH GUIDELINES ON

re tment



OSH GUIDELINES ON TOXIC INDUSTRIAL WASTE TREATMENT

Page1. INTRODUCTION 1

2. SCOPE 1

3. OSH MANAGEMENT PROGRAMME 2Hazard Identification 2Hazard Assessment 3Hazards Control 7Emergency Preparedness 8Principles Of Hazards Control 9

4. WASTE TREATMENT PROCESSES AND CONTROL MEASURES 26Drum Handling and Washing 27Reduction/Oxidation (Redox) 28Neutralisation 30Precipitation 32Coagulation and Flocculation 34Sedimentation and Clarification 36

Filtration 38De-watering / Filter Press 39Fixation and Stablisation Systems 41Evaporation, Distillation and Condensation (Solvent Recycling) 43Incineration 44

5. OTHER MEASURES 47Confined Space Hazards Control 47

Preventive Maintenance 50Management of Change 51Emergency Preparedness and Response 52

6. REFERENCES 54

CONTENTS



OSH Guidelines on Toxic Industrial Waste Treatment

1. INTRODUCTIONIndustrial waste is an unwanted product and by-product of

manufacturing processes and results from or is incidental tooperations in the industry. However, we should not take industrialwaste lightly as it is a mixture of complex substances, thus,creating its potent nature when handled improperly. Neglecting toproperly store, handle, treat and dispose industrial waste wouldnot only jeopardise workers’ health and safety but also causeenvironmental pollution. These translate into cost in terms of

compensation, clean-up and lost time due to illnesses andaccidents.

The primary objective of this document is to provide guidance on minimising riskarising or likely to arise from exposure to the many chemicals in the waste treatmentindustry. Details on how to meet legal requirements are also summarised in thisdocument.

2. SCOPEThis set of guidelines is for waste treatment facilities that store, treat and dispose of toxic industrial waste commercially.

The main aim of these guidelines is to address occupationalsafety and health (OSH) issues when treating industrial waste and

to protect the safety and health of workers in a wastewater treatment facility.

The work nature, size and safety and health risks in individualworkplaces vary. The elements of the OSH managementsystem described in these guidelines should be applied asappropriate and integrated into any existing health, safety andenvironment management system. The guidelines should be

customised for the individual workplace.

Where appropriate, other local legislation and availablescientific information can be referred to for guidance. This set

of guidelines should be read together with the draft ‘Code of Practice on HazardousWaste Management’ as well as the ‘Guidelines on Prevention and Control of



OSH Management Programme

3. OSH MANAGEMENT PROGRAMME

An occupational safety and health (OSH) programme to manage wastewater treatment hazards can be incorporated into other existing management systems.The OSH programme should have these elements:

1. Hazard identification2. Hazard assessment3. Hazard control4. Emergency preparedness

The starting point is to identify all hazards with the potential to cause an accident. Anindustrial waste treatment plant is a highly dynamic workplace, where hazards arenumerous and varied. The hazards identified should include physical factors,

chemicals and biological agents.

Based on the chemicals used and the treatment processes that a facility is able tohandle, considerations to workers’ health and safety should include but should notbe limited to:

♦ risk of acute or chronic ill health via inhalation ingestion or dermal absorption;

HazardIdentification

Hazard

Assessment

Hazards Control

Emergency

Preparedness HAZARDMANAGEMENT

3.1 HAZARD IDENTIFICATION




Once the hazard has been identified, the next step is to determine the associatedrisk levels. Hazards can be grouped into three regions known as intolerable,tolerable and negligible risk regions. Hazard assessment is concerned with acombination of the likelihood of occurrence and consequence of the potential hazardbecoming a reality.

AIR MONITORING / WORKPLACE SURVEILLANCE

Under section 59(6) of the Factories Act, regular workplace monitoring is required inany factory in which toxic chemicals are used or given off.

This flow chart shows how air monitoring is carried out:

3.2 HAZARD ASSESSMENT

Identify Areas with HighLevels of Airborne

Contaminants

Carry OutInitial Measurements

Develop Air MonitoringStrategy

Interpret results of Initial Measurements

Carry Out Air Monitoringat Identified Areas




STEP 1:IDENTIFY AREAS WITH HIGH LEVELS OF AIRBORNE CONTAMINANTS

Identify potential areas likely to have high levels of airborne contaminants using thefollowing information: Layout plans Previous workplace monitoring data Material safety data sheets (MSDSs) and site inventories Accident, exposure, injury, and illness records Interviews, inspections, and walkthroughs. Job and task information Standard operating procedures or facility operating manuals Engineering designs and as-built drawings.

The outcome of this element is to link hazards and their locations with specific jobsand tasks and to possible worker exposures from the hazards.

STEP 2:CARRY OUT INITIAL MEASUREMENTSInitial measurements can help narrow the scope of air monitoring by determining theconcentrations of airborne contaminants. So, areas that show higher concentrationsof airborne contaminants would have to do a round of air monitoring to determineworkers’ exposures during a typical workday or for a specific task.

Initial measurements can be made with direct reading instruments like gas detectionmeters (direct readings displayed on the meter) or detector tubes (that indicateconcentrations using colour change).

STEP 3:INTERPRET RESULTS OF INITIAL MEASUREMENTSIf the results of the initial measurements are high, this indicates that comprehensive

air monitoring has to be done to determine the actual worker exposure or the actualconcentration over a typical shift or during a specific job.

If initial measurements are low, air monitoring need not be done. When there arechanges in operations or processes, re-assessment has to be done.




♦ Accredited laboratories.

♦ Validated sampling and analytical methods.

♦ Appropriate permissible exposure levels (PELs).♦ The minimum number of samples.

♦ The length of the sampling period.

Coordination with occupational health specialists may be required as medical results(blood tests, urine tests, chest x-rays etc.) can indicate high exposures to chemicals. Air monitoring and medical surveillance can complement each other to give a better

picture of workers’ exposures.

STEP 5:CARRY OUT AIR MONITORING AT IDENTIFIED AREAS A competent person should conduct quantitative air monitoring and sampling. Thesteps involved are:

♦ Establish baseline data for workers’ exposures and workplace monitoring.

♦ Document regulatory compliance.

♦ Inform management and workers of exposures.

Clear, concise records of monitoring and sampling should be maintained. Theseshould include the model and serial numbers of all equipment used, calibration data,and site conditions.

Monitoring and sampling results should be compared to the PELs. Interpretation of all results should be made by a competent person.

Example of Analysis and Interpretation Outcomes

If . . . Then . . .

Monitoring and sampling results indicateexposures are not above the PELs.

Health hazards do not pose thepossibility for worker over-exposure.

Health hazards are not significant. Conduct periodic re-evaluation.Monitoring and sampling results indicateexposures are above the PELs.

Worker exposures are potentiallyhazardous.

Health hazards are present. Consider hazard control measures;conduct periodic re-evaluation.




If new hazards are introduced, or there is a significant change in the hazardpotential, a re-evaluation should be conducted as soon as possible. In addition, re-

evaluation may be triggered by the introduction of new hazardous materials,modification of workplace controls, changes in process conditions or work practices,or new toxicological information or regulatory standards.

Re-evaluation involves reexamining the operation and exercising professional judgment. Even if there is no significant change in the operation, periodic re-evaluation is needed to ensure that the exposures do not change over time.

The frequency of re-evaluation should be based on the air monitoring results asfollows:

If the concentration in the air is: Regular air monitoring should be done:

10-50% PEL At least once a year

50-100% PEL At least twice a year

>PEL At least four times a year

For concentrations above 50% PEL, control measures should be taken to reduceconcentrations to less than 50% PEL.

For more details on monitoring methods, selection of measurement techniques /equipment and sampling strategies, please refer to the “Guidelines on Preventionand Control of Chemical Hazards”.

When assessing risks of exposure to contaminants in working environments, theresults of air sampling or concentration measurements are compared with their PELs. Two types of PELs are specified in the Factories (Permissible ExposureLevels of Toxic Substances) Notification:

• PEL (Long Term) is the maximum time-weighted average (TWA)concentration of a toxic substance to which persons may be exposed over an8-hour workday or a 40-hour workweek.

• PEL (Short Term) is the maximum TWA concentration to which persons maybe exposed over a period of 15 minutes during the workday.

To determine compliance with PEL, sample(s) should be collected to cover theperiod for which the exposure standard is defined i e a 15-minute sampling period




To evaluate whether an overexposure occurs for cases where more than onechemical is sampled, one has to see whether these chemicals have similar or

different toxicological effects.

Please refer to the Factories (Permissible Exposure Levels of Toxic Substances)Notification for more information on such evaluation.

The PELs of some of the common toxic substances can be found in the “Guidelineson Prevention and Control of Chemical Hazards”.

Under section 59 of the Factories Act, any process or work that may give off toxic,irritating or offensive dust, fumes or other contaminants needs to be controlled byone or more of these measures:

♦ Carrying out the process or work in isolated areas

♦ Carrying out the process or work in closed systems or vessels♦ Providing adequate ventilation

♦ Providing a local exhaust ventilation (LEV) system

♦ Carrying out the process wet.

Under section 60 of the Factories Act, workers have to be protected against harmfulprocesses or substances by:

♦

Substituting harmful substances, processes or techniques with less harmful ones♦ Carrying out hazardous processes in separate areas

♦ Preventing liberation of harmful substances that may be inhaled, absorbed or ingested with effective means

♦ Placing warning signs at areas with special risks.

Following hazard assessment, hazards need to be reduced to the tolerable region.Those in the tolerable region will only be reduced if it is cost-effective to do so and

those in the negligible region could be left alone. Any method of risk reduction willinvolve reducing the consequence, reducing the probability of occurrence or reducing both parameters.

Generally, reduction in severity of the consequences is usually done in the earlydesign stages of a project’s life cycle Usually reduction in the probability of the

3.3 HAZARDS CONTROL




Only when isolation of hazards / substitution, engineering and administrativemethods are not reasonably practical, PPE should be used. PPE only controls the

degree of workers’ exposure. It still allows direct access to hazardous operations or locations. As PPE has its own limitations, dependence on PPE alone is notencouraged. See section on PPE below for more details.

Hierarchy of Controls Examples

ISOLATION /

SUBSTITUTION

• Covered tanks, sumps

• Closed loop system

•

Substitute with less hazardous operations /chemicals

ENGINEERINGCONTROL

• Local exhaust ventilation (LEV)

• Dilution ventilation

• Automated feed of waste

• Automated dosing of chemicals

• Online sensors

• Process re-design and re-engineering

ADMINISTRATIVE

• Safe work procedures

• Rotation/shift work

• Hazard communication

• Permit-to-work system

• Barriers and warning signs

PERSONALPROTECTIVE

EQUIPMENT (PPE)

• Respiratory protection

• Protective clothing

• Hearing protection

• Fall protection

• Head protection

• Foot protection

It has to be recognised that no matter how carefully the previous three elements areimplemented, the chance of an accident occurring is still there. The role of emergency preparedness is that of being completely ready to take action when anunexpected accident occurs or an incidental threat to become serious. This is doneto minimise injury to personnel damage to or loss of property or pollution of the

Most

preferred

Leastpreferred

3.4 EMERGENCY PREPAREDNESS



Principles of Hazards Control

Under section 59 of the Factories Act, removal of dust, fumes from the workplace isrequired to protect workers’ health and safety.

Under section 60 of the Factories Act, workers have to be protected against harmfulprocesses and substances.

To ensure that workers are adequately protected, the following control measures arerecommended:

1. ISOLATION OF HAZARDS / SUBSTITUTION

Isolation and substitution should always be considered. Isolation contains hazardsaway from worker exposure while substitution removes hazards at the source.

COVERED TANKS, SUMPS AND PITSWhenever practical, cover all tanks, pits, sumps. This reduces the risk of workersfalling into tanks and also, workers’ exposure to chemicals that have been generatedfrom the treatment processes.

When a tank is covered, a level sensor is required to indicate the level of liquid in the

tank. The liquid level sensor will prevent overflow in the tank and also indicate tell-tale signs of leaks.

If covering the tanks is not possible, barricades should be placed to prevent falls.

SUBSTITUTIONSubstitution replaces a hazard with a less hazardous alternative. Examples include:

More Hazardous Chemicals / Materials Replaced with:

Acidic cleaners, alkaline cleaners Neutral cleaners

Solvent cleaners Water-based cleaners

Organic solvents Water

Chlorinated solvents Non chlorinated solvents

PRINCIPLES OF HAZARDS CONTROL




For systems handling gases and vapours, the economic optimum velocity is 1000 –

2000 fpm. For transporting particulates, a minimum design velocity is required toprevent settling and plugging of the duct. Excessively high velocities are wasteful of energy and may cause rapid abrasion of ducts.

Nature of Contaminants Design Duct Velocity Examples

Gases, vapours, smoke1000 – 2000 fpm5.08 – 10.16 m/s

All gases, vapours, smoke

Fumes 2000 – 2500 fpm10.16 – 12.7 m/s Welding

Very fine & light dust2500 – 3000 fpm12.7 – 15.24 m/s

Cotton lint, wood, flour

Dry dust & powder 3000 – 4000 fpm15.24 – 20.32 m/s

Cotton dust, rubber dust

Average industrial dust3500 – 4000 fpm

17.78 – 20.32 m/s

Grinding dust, granite dust,clay dust, asbestos dust,foundry / material handling

Heavy dust4000 – 5000 fpm

20.32 – 22.86 m/sSawdust, metal turnings,sandblast dust, lead dust

Very heavy dust>4500 fpm>22.86 m/s

Lead chips, moist cement,dust, asbestos chunks

Dilution VentilationDilution ventilation improves the general airflow in the work area, making the workenvironment more comfortable. Heat stress on workers is reduced, especially inareas of waste neutralisation and incineration.Dilution ventilation may not effectively reduce workers’exposure to hazards as airborne contaminants are notremoved at the source of generation (in comparison with LEV).

Adequate air should be provided to dilute the contaminants tobelow their PELs.

REMOTE CONTROL DEVICES




PROCESS DESIGN AND RE-ENGINEERINGThe greatest application of process design and re-engineering is to operational

facilities undergoing shut-down periods and maintenance. The earlier that safety isconsidered in the design process, the less it costs to implement and the greater thechance for inherent safety (i.e., the potential dangers have been removed).

However, for existing facilities, safety considerations are manifested extrinsically(e.g., safety is added with devices such as alarms and interlocks and practices suchas equipment redundancy).

SAFE WORK PLACE AND SAFE MEAN OF ACCESSIn general, waste treatment plants are hazardous work places. Therefore, a safework place and a safe mean of access should be provided for workers working in theplants.

Under section 33 of the Factories Act, there shall, so far as is reasonably practicable,

be provided and maintained safe means of access to and egress from every place atwhich any person has at any time to work and every such place shall, so far as isreasonably practicable, be made and kept safe for any person working there.

Where any person has to work at a place from which he would be liable to fall adistance of more than 3 metres or into any substance which is likely to causedrowning or asphyxiation, a secure foothold and handhold shall be provided so far aspracticable at the place for ensuring his safety. Where it is not practicable to provide

a secure foothold and handhold, other suitable means such as a safety belt andfencing shall be provided for ensuring the safety of every person working at suchplaces. Where a safety belt is provided, there shall be sufficient and securedanchorage, by means of a life line or otherwise for the safety belt, and the anchorageshall not be lower than the level of the working position of the person wearing thesafety belt.

Please refer to Singapore Standard CP27:1999 “ Code of Practice for Factory Layout - Safety, Health and Welfare Considerations” for guidelines in planning the layout of factory.

SECURED FENCING




3. ADMINISTRATIVE MEASURES

SAFE WORK PROCEDURESSafe work procedures can dramatically improve workers’ safety and work efficiency.Written operating procedures should be integrated with safe work.

A multi-disciplinary team should develop safe work procedures. The team shouldinclude personnel from various departments doing different types of work. The safework procedure should be thoroughly evaluated prior to implementation, monitoredduring use and modified as working conditions or processes change.

Under section 47A of the Factories Act, safe work procedures shall be establishedand implemented for all work stipulated in the Twelfth Schedule of the Act. No workspecified in the Twelfth Schedule of the Factories Act shall commence unless safework procedures are implemented.

LOCK-OUT PROCEDURESLock-out procedures are procedures to ensure that all energy sources to the relevantplant, machinery or equipment will be isolated, disconnected or discharged. It is toprevent any part of the plant, machinery or equipment from being inadvertentlyactivated or energised.

Under section 24A of the Factories Act, lock-out procedures shall be established andimplemented for the inspection, cleaning, repair or maintenance of any plant,machinery or equipment that, if inadvertently activated or energised, is liable tocause bodily injury to any person. Every person carrying the work shall be fullyinstructed on the lock-out procedures for that work before commencing such work.

PERMIT-TO-WORK SYSTEMPermit-to-work systems shall be implemented for work in any confined space andwork involving the application of heat, or the potential generation of any source of ignition, where any explosive or flammable substance is liable to be present.

Please refer to Singapore Standard CP50:1997 “Code of Practice for Safety in




work they do so that the work can be done safely. Under the Factories Act, classesor description of persons employed in the factory set out in the Schedule of the

Factories (Safety Training Courses) Order shall attend the safety training coursesconducted by the Occupational Safety and Health Training and Promotion Centre or other training institutes approved by the Chief Inspector of Factories.

It is advised that a chemist be in charge of the treatment of toxic industrial waste.Treatment processes involve chemical reactions and a chemist would know besthow to treat toxic industrial waste in a safe manner.

MANAGEMENT OF HAZARDOUS SUBSTANCES PROGRAMME

Generally, waste treatment plants handle a wide variety and large quantity of chemical waste daily. A Hazardous Substance permit shall be obtained from NEA if the hazardous chemicals stored or used are controlled under the Environmental

Pollution Control (Hazardous Substances) Regulations. A programme should beestablished to identify and manage all hazardous chemicals in the plant through theprovision of MSDSs and procedures for proper use, storage, handling andmovement of the hazardous chemicals. The programme should include andincorporate the following:

♦ A register of hazardous chemicals in use in the factory should be maintained.Each hazardous chemical, including waste, should be accompanied with theappropriate MSDS to facilitate risk assessment and training of employees onproper handling techniques and precautionary measures to observe during itsuse, handling and storage.

♦ Procedures for proper receipt, storage, issue, distribution, handling and safe useof the hazardous chemicals should be established.

♦ Competent person(s) who have adequate knowledge of the properties of thehazardous chemicals to administer the control of the chemicals should beappointed.

♦ The prohibition of purchase or trial use of all hazardous chemicals until itschemical, physical and toxicological properties have been reviewed in a riskassessment to determine whether the chemical can be used handled and

Management of Hazardous Substances

Movement of hazardous chemicals




♦ Proper labels on the external walls with information such as the name andproperties of the chemical contained therein and the hazards associated with the

chemicals should be provided.♦ The total inventory of the hazardous chemicals stored in the factory at the

process area or at other designated storage areas should not be in excess of thecapacity necessary for production requirements.

♦ The hazardous chemicals should be stored in designated areas, which aresuitable for the chemicals and secured against unauthorised access. Thechemicals should be returned to the designated areas when not in use.

♦

Incompatible hazardous chemicals must not be stored in the same storage areas.If this is not practicable, they should be stored in areas separated from oneanother by physical barriers such as walls and floors or by other suitable means.

♦ Warning notices specifying the danger of the hazardous chemicals should beplaced at all entrances to any workroom and at appropriate locations wherehazardous chemicals are used or stored. In addition, they should be in languagesunderstood by the relevant persons.

Procedures for disposal of hazardous chemicals must be established andimplemented in accordance with regulatory requirements or manufacturer’srecommendations.

Adequate training must be provided to all personnel and contractors who may beexposed to the hazardous chemicals. Training for related personnel whenever a newhazardous chemical is introduced into the process must also be provided. Under Section 60 of the Factories Act, a competent person shall be appointed to managehazardous substances in a wastewater treatment facility. The competent person hasto attend the “Management of Hazardous Substances” course, and to ensure thathazardous substances are stored, transferred, used and disposed of in a safe

manner.

MEDICAL SURVEILLANCE

Medical surveillance is a system of monitoring thehealth status of persons to determine departures from

Disposal of hazardous chemicals

Training




Under the Factories (Medical Examinations) Regulations, pre-employment and

periodic medical examinations are required for persons who are exposed to thefollowing hazards: Arsenic and its compounds Asbestos Benzene Cadmium and its compounds Compressed Air Cotton

Lead and its compounds Manganese and its compounds

Mercury and its compounds Noise Organophosphates Perchloroethylene (PCE) Free Silica Tar, pitch, bitumen and creosote

Trichloroethylene (TCE) Vinyl chloride monomer (VCM)

Under the Regulations, the examinations are to be conducted by a registereddesignated factory doctor (DFD). A list of DFD is obtainable from the websitehttp://www.mom.gov.sg/ This list can be found under “Occupational Health Service Providers”.

A summary of the types of medical examinations and tests required for personsexposed to hazards, which may be found in the toxic industrial waste treatmentindustry, is given in Appendix 2.

(a) Pre-employment health examinations

For medical surveillance to be effective, it is useful to start from the time a worker begins his exposure to a particular hazard. This pre-employment examinationshould be conducted within three months of employment and the results wouldbe the baseline against which subsequent changes can be compared.

For example, workers exposed to lead are required to undergo a hemoglobin testand blood lead estimation at pre-employment. If he is found to have a low

hemoglobin level i.e. is anemic, he should not be engaged in work involving leadexposure as he would be at greater risk of developing lead poisoning. Anincrease in the blood lead levels in subsequent examinations compared to thebaseline would suggest that lead has entered the worker’s body. If leftunchecked, the worker may eventually be poisoned.

http://www.gov.sg/mom/wpeaw/indushea/ih.htm

http://www.gov.sg/mom/wpeaw/indushea/ih.htm




Workers with abnormalities which are not related to work may sometimes need tobe removed from exposure and treated before returning to the job. For example,

lead workers with iron deficiency anemia should be removed from further leadwork until they have been treated.

The nature of the examinations and the frequency of such examinations dependon the type of disease and the degree of exposure to the hazard in a particular work situation.

Good record keeping is vital. Records of examinations conducted should be kept

in the format given in Appendix 3. Summary reports of these examinationsshould be submitted to the Occupational Safety and Health Division,Ministry of Manpower. Worker’s exposure information should be kept for atleast five years from the last date of examination in the format given in Appendix 4.

All workers with abnormal test results should be examined by your designatedfactory doctor (DFD).

LABELLINGLabelling aids the identification of wastes and wastewaters. Thus, the duty of labelling falls on not only the waste treatment facility but also on the generator of thewaste.

It is recommended that hazardous waste labels have the following information:

Title A “Hazardous Waste” heading

Identity of wasteChemical name/common names/synonyms, with wastetype

Identity of generator Generator’s name, address and contact number(s)

Symbol Graphical representation of the hazardous waste’s nature

Particular risk(s)Inherent/potential harm that the hazardous waste may/cancause

Safety precaution(s) Warnings and instructions in relation to the risk(s)

An example of the label template:

Hazardous Waste




SECURITY AND WARNING SIGNS

Security and warning signs limit worker and third party access to the work areas andsite hazards. Security measures can prevent:

♦ Exposure of unauthorized, unprotectedpersonnel to work-site hazards;

♦ Spread of contamination;

♦ Access by thieves, vandals, or persons seekingto abandon other wastes on the work-site; and

♦ Interference with safe work procedures.

SecuritySite security can be maintained during off-hours by assigning trained in-house

personnel for surveillance, using security guards to patrol the plant’s boundary, andsecuring equipment.

Warning signsPhysically identifying and posting warning signs are important elements of work-sitehazard communication. Site work zones are to be clearly identified with signs at theentrance of each work zone. There should be specific hazard posting requirementsfor confined spaces, asbestos, noise, carcinogens, corrosive chemicals andflammable storage areas. Signs are to be securely affixed, resist adverseenvironmental conditions, and reflect changing conditions and hazards at the work-site.

Signs are spaced to ensure visibility upon approach to the boundary of a work zoneor a hazard. At least one sign is to be visible on each side of the boundary and from

each direction of approach.

Work zone and hazard posting should: Identify all types of hazards sufficient to maintain worker recognition and safety; Be installed immediately after the work zones are established and the hazards

are identified; and




Provide safety guidance, such as lessons learned or amount of breathing air left; Monitor or confirm well-being or exposure, stress, or confusion; and

Maintain site control and facilitate stop-work actions or work-site evacuation.

A waste treatment log should be maintained to track the different types of waste thathas been treated in the facility. See Appendix 5 for a recommended format.

Verbal communication can be impeded by background noise from heavy equipmentor by PPE. Thus, for effective communication, commands are pre-arranged andinclude both visual and verbal cues.

A primary and back-up communication system is necessary; both should be checkeddaily. All communication devices must be spark-free. Communication equipment iscoordinated with explosive experts if explosives are used at the site.

Individual workers should be identified by names placed on their PPE or by color-coding or numbers.

Communication between heavy-equipment operators in enclosed cabs and workerson foot is critical.

External communication is between onsite and offsite personnel and is used to:• Coordinate emergency response; and• Maintain contact with outside personnel such as management.

External communication between generator and toxic industrial waste collector isimportant. With adequate knowledge of the toxic industrial waste and itscomposition, the collector is able to know:

♦ The best way to treat the waste collected

♦ If there are constituents in the waste that may be incompatible with treatmentchemicals

Currently, NEA has an e-tracking system that allows generators to declare the typeof toxic industrial waste generated and the licensed collector that will be treating thewaste. This system tracks the status of the waste from its point of generation to thereceiver’s end.




PPE should alwaysbe used as the last

line of defence.

(2) while engineering controls are being developed, or (3) during emergencies.

The type of PPE and the material from which the PPE is made are to protect againstthe hazards present. Work-site managers should be aware that no singlecombination of protective equipment and clothing can guard against all hazards.Moreover, because every work-site is different and the degree of known or unknownhazards varies, the PPE ensemble required is likely to change as work progresses.

PPE should be selected based on three distinct tasks:

Conduct a hazard characterisation and exposure assessment (see Section 3) toidentify (1) actual or potential hazards and (2) possible exposure routes;

Organise and analyse the data and select PPE based on the type of hazard, thelevel of risk, and the seriousness of potential harm from each identified hazard;and

Make certain that the PPE fits and that it protects against the hazards, andperiodically reassess the hazards and PPE selection.

PPE include respirators, protective clothing, hearing protectors, head protectors,face/eye protectors, hand protectors and foot protectors. Careful selection andproper use of PPE should protect the respiratory system, skin, eyes, face, hands,feet, head, body and hearing.

The purpose of PPE is to shield or isolate individuals from the chemical, physical andbiological hazards that may be encountered at a waste treatment facility. For any

given working condition, PPE should be selected to provide an adequate level of protection to the worker.

No single combination of protective equipment and clothing is capable of protectionagainst all hazards. PPE should be used together with other hazard control methods,as the use of PPE alone can create new problems: heat stress, physical andpsychological stress, impaired vision, reduction in mobility and communication.

The limitations of PPE should be fully taken intoconsideration before use. PPE worn should also beappropriate to the hazards exposed to, so that the hazardscan be combated effectively with the right PPE.




the top of the trailer container or ISO-tank. Please refer to section 33 of the Factories Act for more details on safe means of access and safe place of employment.

RESPIRATORY PROTECTION

Special requirements for respiratory protection include: Preparing a written respiratory protection programme; Medically evaluating, training, qualifying, and fit-testing workers

for specific respirator types; and

Checking for any special respiratory protection requirements(e.g., for asbestos, lead, nickel or cadmium).

Since the main route of exposure to toxic substances is viainhalation, care must be taken to select, use and maintainrespiratory protection devices.

Respiratory protective devices consist of a facepiece connected to either an air source or an air-purifying filter. The relative advantages and disadvantages of respiratory devices are listed below:




22

Relative Advantages and Disadvantages of Respiratory Protective Equipment

Types of

respiratoryprotection

Advantages Limitations

AIR-SUPPLYING

Self-ContainedBreathing Apparatus(SCBA)

♦ Provides highest level available level of protectionagainst airborne contaminants and oxygendeficiency.

♦ Provides highest level of protection under strenuous work conditions.

♦ Bulky and heavy.

♦ Finite air supply limits work duration.

♦ May impair movement in confined spaces.

Positive-PressureSupplied-Air Respirator (SAR) or Air-Line

Respirator

♦ Enables longer work periods than an SCBA.

♦ Less bulky and heavy than an SCBA.

♦ Protects against most airborne contaminants.

♦ Not for use in atmospheres immediately dangerousto life or health (IDLH), unless escape-only SCBAis provided for immediate emergency respiratoryprotection in case of air-line failure.

♦ Not for use in oxygen-deficient atomospheres (<19.5% O2), unless escape-only SCBA is provided

for immediate emergency respiratory protection incase of air-line failure.

♦ With increased hose length, minimum air flow maynot be delivered to facepiece.

♦ Airline is vulnerable to damage, chemicalcontamination and degradation. Decontaminationof hoses may be difficult.

♦

Worker must retrace steps to leave work area.♦ Supervision/monitoring of the air supply line is

required.




23

AIR-PURIFYING Air-Purifying

Respirator [includingpowered air-purifyingrespirators(PAPRs)]

♦ Enhanced mobility during work.

♦ Lighter than SCBA.

♦ Cannot be used in IDLH or oxygen-deficientatmospheres.

♦ Limited duration of protection. Difficult to gaugesafe operating time in field conditions.

♦ Protects against specific contaminants only.

♦ Protects against specific concentrations only.

♦ Air monitoring of contaminants and oxygenrequired.

♦ Can only be used against gas and vapour

contaminants with adequate warning properties.♦ Or, for specific gases or vapours provided that the

service life-span is known and a safety factor isapplied or if the unit has an end-of-service-lifeindicator.

For more details on respirators, please refer to Singapore Standard CP 74:1998, Code of Practice for Selection, Use andMaintenance of Respiratory Protective Devices.




Protection Factor The protection factor of a respirator is determined experimentally. This number

indicates the relative difference in concentrations of substances outside and insidethe facepiece that can be maintained by the respirator.

For example, the protection factor for a full-facepiece air-purifying respirator is 50.Persons wearing this respirator can be protected in atmospheres containingchemicals at concentrations that are up to 50 times higher than the appropriatelimits.

See the table below for a list of respirators and their protection factors.

* Respiratory Protection Equipment and Associated Protection Factors:

Respirator Protection

factor

Air-purifying respirators – dust masksSingle-use dust maskQuarter maskHalf maskFull-facepiece dust maskPowered dust mask

551050

1000

Air-purifying respirators – chemical cartridgeHalf-facepiece maskFull-facepiece mask

1050

Supplied-air respiratorsDemand half facepiece maskDemand full facepiece maskPressure-demand half-facepiece maskPressure-demand full-facepiece maskContinuous-flow helmet or suit

1050

100020002000

SCBAs (self-contained breathing apparatus)Open-circuit demandOpen-circuit pressure demandClosed-circuit, oxygen cylinder type(all are full facepiece)

5010000

50




Respirator SelectionRespiratory protection is of primary importance since inhalation is one of the major

routes of exposure to chemicals. Respirators consist of a facepiece connected to anair source or an air-purifying device.

Respirators with an air source:

♦ Self-Contained Breathing Apparatus (SCBA)

♦ Supplied-Air Respirator (SAR) or Air-Line Respirator

Respirators with an air-purifying device do not have a separate air source but filters

out contaminants in the ambient air prior to inhalation.

This flow chart below shows how a suitable respirator may be selected:

Can use air-purif yingC

If i / i f * PEL

LBelow IDLH?

Define MUC IDLH and PEL.

No

Yes

Define maximum expected concentration.

Is oxygen deficiency possible?

No

Yes

Define contaminant(s) .

Use SCBA orair-line

Yes

Unknowncontaminants

W t T t t P d C t l M



Waste Treatment Processes and Control Measures

4. WASTE TREATMENT PROCESSES AND CONTROL MEASURES

Typical wastewater treatment processes:

In the following pages, recommended control measures are outlined to address potential hazards arising from each of thewastewater treatment processes.

Chemical

ReductionNeutralisation Sedimen-

tation

FiltrationFinal pHcontrol

S l u d g e

Sludge De-wateringwith Filter Press

Dewatered sludge is sentfor fixation and thenlandfilled

Return line forliquid effluent

Supernatantis filtered

Incoming

wastewaterTreatedEffluent

ChemicalOxidation

Incomingwastewater

Acids / Alkalis

Reducing agents

Oxdising agents

Acids / Alkalis





Drum Handling and Cleaning

The ProcessWaste-containing drums, carboys, bottles or tins have to be emptied out either bypouring or with the use of a pump. The containers are then washed and rinsed after the contents have been emptied out.

Recommended Control Measures

The following are measures that should be taken to address potential hazardsarising from the drum handling and cleaning process:

Recommended Control Measures Potential Hazards Addressed Build enclosures or curtains around

the washing area Use pumps whenever possible to

transfer waste Minimise manual handling Install effective local exhaust

ventilation (LEV) systems to removeairborne contaminants (sincegaseous products, fumes and mistsare likely to be produced duringwashing and rinsing)

Use impervious overalls, faceshieldand / or chemical goggles, chemicalresistant and cut-proof gloves andimpervious boots

1. Skin burns or rash and eye irritationfrom direct skin and eye contact withchemicals

2. Splashes or fumes generated duringpouring of chemical waste andtreatment chemicals into thetreatment tanks





Reduction / Oxidation (Redox)

The ProcessElectroplating waste has to be chemically reduced or oxidised prior to discharge into watercourses and sewers, as required by theNational Environment Agency (NEA).

Waste containing chromic acids (where chromium exists in the Cr 6+

state) are reduced to trivalent chromium (Cr 3+

) using reducingagents / reducers like sodium bisulphite.

Waste containing cyanides (CN-) are oxidised using oxidising

agents / oxidisers like hydrogen peroxide (H2O2).


The following are measures that should be taken to address potential hazardsarising from the reduction or oxidation process:

Recommended Control Measures Potential Hazards Addressed

Avoid mixing or treating waste withanother type of waste, unless thecompositions are known and

appropriate measures are in place tocontrol any potential hazards

Conduct laboratory testing prior totreatment to ascertain the type of hazardous substances that may begenerated

Generation of hazardous substancesfrom reactions among different types of waste

Store oxidising agents and reducingagents for the treatment of thewastewater separately as they areincompatible

Store chromic acid waste and cyanidewaste separately

1. Uncontrolled reaction betweenoxidisers and reducers during storage

2. Mixing chromic acid waste andcyanide waste leads to uncontrolledreactions with unknown products andhazards

Implement noise control measures at

ChemicalReduction

ChemicalOxidation

Reducing agents

Oxdising agents






Build enclosures around reactors or

cover all reactors Install effective local exhaust

ventilation (LEV) systems to removeairborne contaminants (sincegaseous products, fumes and mistsare likely to be produced duringoxidation or reduction)

Install automated dosing systems

Install fixed piping for dosing of oxidisers / reducers

Install an Oxidation / ReductionPotential (ORP) meter linked to thedosing system to monitor the extentof the redox reaction and keep thetreatment process within control

Use impervious overalls, faceshieldand / or chemical goggles, imperviousgloves and impervious boots

Carry out redox reactions in separatetanks

Use lifting / handling devices


2. Splashes or fumes generated duringpouring of chemical waste andtreatment chemicals into thetreatment tanks

3. Back injury from manual pouring of waste chemicals / treatmentchemicals into treatment tanks

Establish and implement safe workprocedures

Conduct gas testing by a competentperson

Work with continuous forcedventilation in confined spaces

1. Confined space hazards2. Poisoning by toxic fumes or vapours3. Suffocation due to lack of oxygen





Neutralisation

The Process Acid-base neutralisation is one of the most common chemicalprocesses used in waste treatment. Neutralisation of an acidicor alkaline waste is the addition of acids or bases to the wasteto alter the pH to a more neutral level – in the range of 6 to 9.

Acidic waste may be neutralised with slaked lime [Ca(OH)2],caustic soda (NaOH) or soda ash (Na2CO3). Alkaline waste may be neutralised with

sulphuric acid (H2SO4) or hydrochloric acid (HCl). Acids/bases are added to thewaste in an agitator vessel with a pH sensor to control the feed rate.The neutralisation reactions are exothermic and care needs to be taken to avoidexcessively high temperatures, which can result in unsafe operating conditions anddamage to equipment.

Fumes and mists may be generated due to the increased temperatures from theexothermic neutralisation process.


The following are measures that should be taken to address potential hazardsarising from the neutralisation process:


Avoid mixing or treating waste withanother type of waste, unless thecompositions are known andappropriate measures are in place tocontrol any potential hazards


Generation of hazardous substancesfrom reactions among different types of

waste

Wash down with water the inside of the 1 Unknown reactions and hazardous

Neutralisation

Acids / Alkalis




Recommended Control Measures Potential Hazards AddressedPlace barricades or fences around

neutralisation pits

Accidental falls into pit / sump

Implement noise control measures atareas with noise levels > 85 dBA

Control excessive noise at the source(e.g. pumps, compressors, exhaustfans)

Implement a hearing conservationprogramme (HCP)

For more details, please refer to the‘Guidelines on Hearing ConservationProgramme’

Noise induced deafness

Install fixed piping for dosing of acid/alkalis

Install automated dosing systems Install a pH meter linked to the dosing

system to monitor the extent of theneutralisation and maintain thetreatment process at controlledconditions

Use lifting / handling devices for transferring of waste from tank to tank

Cover all neutralising pits andreactors

Build enclosures around all reactors. Install local exhaust ventilation (LEV)

to remove airborne contaminants Install blowers to increase airflow in

the surrounding work area Use chemical resistant overalls,

chemical goggles and / or faceshields(as appropriate), impervious glovesand chemical boots

Use respirators with cartridges /canisters for protection againstalkaline and acidic fumes


2. Splashes or fumes generated duringpouring of chemical waste andtreatment chemicals into thetreatment tank

3. Poisoning or other health effects fromgaseous products, fumes and mistslikely to be produced duringneutralisation


Establish and implement safe work




Precipitation

The ProcessChemical precipitation is a common method for removing heavy metals inwastewater. Depending on the metal and the pH of the wastewater, metalsprecipitate, forming insoluble hydroxides. The solubility of metal hydroxides isdependent on pH and the optimum pH is unique to each metal hydroxide.

Neutralisation of an acidic waste stream can cause precipitation of heavy metals.Heavy metals are removed and the acidic waste stream is neutralized in one

process.


The following are measures that should be taken to address potential hazardsarising from the precipitation process:





Wash the insides of the neutralisationtank with water

Treat the water used for washing prior to discharge

1. Cross-contamination of waste maylead to unknown chemical reactions

and hazardous products2. Water pollution

Place barricades or fences aroundprecipitation pits

Accidental falls into precipitation pit /sump

Implement noise control measures at




Recommended Control Measures Potential Hazards Addressed Cover all neutralising pits and

reactors Build enclosures around reactors or mixing tanks

Install effective local exhaustventilation (LEV) to remove airbornecontaminants (especially gaseousproducts, fumes and mists producedduring the exothermic precipitation

process) Increase airflow in the work area with

dilution ventilation (blowers) Install fixed piping for dosing of acids

/ alkalis and for transferring of waste Install automated dosing systems to

reduce human contact and exposureto chemicals

Install a pH meter linked to the dosingsystem to monitor the extent of theprecipitation and maintain thetreatment process at controlledconditions

Use chemical resistant overalls,chemical goggles and / or faceshields

(as appropriate), impervious glovesand chemical boots

Use respirators with cartridges /canisters for protection againstalkaline and acidic fumes

1. Inhalation and absorption of chemicalfumes, mists and airbornecontaminants in the work area

2. Poisoning or other health effects fromgaseous products, chemical fumesand mists likely to be produced duringprecipitation





1. Confined space hazards

2. Poisoning by toxic fumes or vapours3. Suffocation due to lack of oxygen

The occupational safety and health considerations for both neutralisation and




Coagulation and Flocculation

The ProcessPrecipitation of heavy metals and suspended solids can be greatly enhanced byadding various water-soluble chemicals and polymers that promote coagulation andflocculation. Coagulation and flocculation are used to settle suspended solids inwastewater when the normal sedimentation rates are too slow to provide effectiveclarification.


The following are measures that should be taken to address potential hazardsarising from the coagulation and flocculation process:



Conduct laboratory testing or jar testsprior to treatment to ascertain thetype of hazardous substances that

may be generated and to determinethe best coagulant for each type of waste









Control Measures Potential Hazards AddressedPlace barricades or fences aroundsedimentation and clarification pits

Accidental falls into the sedimentationand clarification pits / sumps









1. Confined space hazards2. Poisoning by toxic fumes or vapours3. Suffocation due to lack of oxygen




Filtration

The ProcessSuspended solids can be removed from the liquidphase via filtration. A porous medium acts as a filter that traps suspended solids that add to the thicknessof the porous medium. When the porous mediumbecomes saturated, fluid pressure through themedium can become very high. The medium can berecharged by back-washing the filter.


The following are measures that should be taken to address potential hazardsarising from the filtration process:

Control Measures Potential Hazards Addressed Avoid mixing or treating waste with

another type of waste, unless thecompositions are known andappropriate measures are in place tocontrol any potential hazards

Conduct laboratory testing prior to

treatment to ascertain the type of hazardous substances that may begenerated


Install fixed piping system for thetransfer of waste

Use chemical resistant overalls,chemical goggles and / or faceshields(as appropriate), impervious gloves

and chemical boots Use respirators with cartridges /

canisters

1. Poisoning or other health effects fromgaseous products, fumes and mistslikely to be produced during filtration

2. Back injury from manual pouring of

waste chemicals / treatmentchemicals into treatment tanks


Filtration

Supernatantfrom

clarificationis filtered

Filtrationmediainside




De-watering / Filter Press

The ProcessPlate and frame filter presses are commonlyused to remove water from sludge. Thisprocess produces filter cakes with a solidscontent as high as 50%.

The filter press is made up of vertical platesheld on a frame and between each plate is

a filter medium (usually made of wovenplastic). Liquids are allowed to pass throughthe filter medium while solids are collectedon the surface of the fabric.

The slurry to be de-watered is fed to the filter press until the flow rate dropssignificantly. Flow to the filter press is stopped, pressure is relieved and the press isopened to remove the solid filter cake. The solid filter cake would undergo fixation

and stabilisation to prevent hazardous substances from leaching out of the cake. Thestabilised solid waste is then land-filled.


The following are measures that should be taken to address potential hazardsarising from the de-watering / filter press process:


Avoid mixing or treating waste withanother type of waste, unless thecompositions are known andappropriate measures are in place to

control any potential hazards Conduct laboratory testing prior to

treatment to ascertain the type of hazardous substances that may begenerated

Generation of hazardous substances

from reactions among different types of waste

S l u d g e SludgeDe-

wateringwith FilterPress

De-wateredsludge is

sent forfixation andland-filled

Return line forliquid effluent

to neutralisationtank




Cover all bins that contain sludge tominimise evaporation of chemicalsinto the atmosphere and to reduceodours in the work area

Install blowers to increase airflow inthe surrounding work area

Use chemical resistant overalls,chemical goggles and / or faceshields(as appropriate), impervious glovesand chemical boots

Use respirators with cartridges /canisters

Poisoning or other health effects fromdirect contact with solid filter cakes


Control excessive noise at the source(e.g. filter presses, pumps,compressors, exhaust fans)




Ensure that trade effluent discharged intothe public sewer / watercourse /controlled watercourse has to be within

the allowable discharge limits stipulatedby NEA

Water pollution




Stabilisation and Fixation Systems

The ProcessStabilisation and fixation systems are generally designed to reduce the final releaseof hazardous constituents of the treatment. This is done by:

Reducing the solubility of the hazardous constituents; Reducing the exposed area that may allow migration of the contaminants; or Detoxifying the contaminants.

Wastes are incorporated into a solid matrix with binding agents or polymers. Some of

these common binding agents include: ash, cement, Portland cement (mix of oxides of calcium, silica, aluminium and iron).

Wastes are usually dewatered first before solidification to reduce the ultimate volumeof stabilised waste for disposal, making it more cost effective to dispose of thehazardous waste.


The following are measures that should be taken to address potential hazardsarising from the stabilisation / fixation process:



Conduct laboratory testing prior totreatment to ascertain the type of hazardous substances that may be

generated


Add water to powders instead of powders to water

Install a sprinkler system to wetpowders



Evaporation, Distillation and Condensation (Solvent Recycling)

The ProcessEvaporation of liquids (usually valuable hydrocarbons) reduces the volume of wastethat must be ultimately be treated or disposed of. Recycling valuable solvents is alsomore cost-effective than buying fresh solvents.

Fractional distillation yields solvents of higher purity as compared to simpleevaporation and condensation products.

Batch distillation systems are commonly used to recover and recycle volatile liquids.


The following are measures that should be taken to address potential hazardsarising from the solvent recycling process:

Recommended Control Measures Potential Hazards Addressed Install effective local exhaust

ventilation (LEV) systems to removeairborne contaminants like organicvapours and volatile hydrocarbons

Install blowers to increase airflow inthe work area

Enclose the entire evaporation andcondensation unit in a closed loop

system For the drumming process, provide

displaced vapour control equipment.Displaced vapour control equipmentmay include:

∗ A return line to the condenser unit

or,∗ Ducting to direct displaced

vapours to an exhaust with anactivated carbon filter

1. Poisoning or other health effects from

organic gaseous products,hydrocarbon fumes and mistsgenerated during solvent recycling

2. Accumulation of flammables in thework area leading to potential firesand explosions




Incinerators

The Process

With complete combustion, incinerators are able to burn off organic wastes intomainly, carbon dioxide (CO2) and water. If the organics are nitrogen- or sulphur-containing hydrocarbons, nitrogen dioxide (NO2) and sulphur dioxide (SO2) areproduced.

Thermal destruction of hazardous wastes is the controlled exposure of waste toelevated temperatures. When properly designed, operated and maintained, thermal

destruction systems can destroy hazardous organic wastes and significantly reducetheir volume.

Some design considerations of an incinerator include:

Temperature Incinerator temperature is essential in ensuring proper destructionand removal efficiency of hazardous waste. The thresholdtemperature (temperature of operation to initiate thermaldestruction of hazardous waste) must be achieved.

ResidenceTime

The volume of the incinerator determines the residence time for any given flow rate. The products of incomplete combustion mustremain at the designed incinerator temperature long enough toensure their conversion to carbon dioxide and water.

Unless these desirable combustion products are realised,additional downstream processing is necessary.

Turbulence Effective use of turbulence can lessen the severity of operatingtemperature and residence time requirements. The configuration of the incinerator affects its ability to destruct hazardous wastes.

Pumps, blowers and baffles should be selected based on the typeof waste to be incinerated. Heat transfer and fluid flow should beconsidered in the turbulence requirements for the design of thethermal destruction unit.

Pressure Incineration should operate slightly negative or vacuum to reducefugitive emissions. For incineration systems with positive elevatedpressures, non-leaking incinerators are required.

Air Supply The reactions of combustible components require air for completecombustion. The incinerator must have sufficient oxygen or air




RefractoryMaterials

Incinerators must be insulated with refractory materials to operateeffectively at high temperatures. Also, refractory materials containheat released from the incineration within the unit.

The erosion and abrasion characteristics of wastes beingincinerated can cause considerable wear on the incinerator refractory. Refractory materials may be subject to chemicalreactions between hazardous wastes and their destructionproducts. Hence, they must be versatile and able to withstandphysical and chemical attack. Also, they must be capable of

maintaining its strength properties under high-temperatureconditions.


The following are measures that should be taken to address potential hazards

arising from the incineration process:


♦ Install a flame failure detectionsystem

♦ In the event of flame failure, purgeany flammable gas mixture in the

furnace and combustion spacesbefore re-lighting.

1. Incinerator failure2. Burns and heat exposure3. Fire

4. Explosion

During manual mixing of organic sludge,workers should wear PPE: Impervious gloves Impervious aprons Impervious boots Faceshield and / or goggles (as

appropriate) Respirators with cartridges for organic

vapours

It is recommended that mixing be done

Poisoning or other health effects from

organic gaseous products, hydrocarbonfumes and mists generated during mixing




Ensure that flue gas from the incinerator meet the special emission standards for waste incinerators set by NEA.

Air pollution

Other Measures



5. OTHER MEASURES

CONFINED SPACE HAZARDS CONTROL

Safe Work ProceduresUnder section 47A and the Twelfth Schedule of the Factories Act, safe workprocedures are required for work in confined space. Safe work procedures shall beestablished and implemented before work in a confined space can commence.

Safe work procedures should include but should not be limited to the

following:

Evaluation of the purpose of entering the confined space. Identification & assessment of all hazards when working in theconfined space. Control and prevention of the hazards.

Please refer to Singapore Standard CP 84 ““ Code of Practice for Entry into and Safe

Working in Confined Spaces” for guidelines on the permit-to-work system.

General Requirements Identify Confined Spaces

All confined spaces have to be clearly identified, documented and labelled.

Warning SignsWarning signs are a form of hazard communication and should be displayed at

the entrance to confined spaces and also, near the access point(s) to confinedspaces.

Warning signs also prevent unauthorised entry, and remindworkers to get approval via the permit-to-work system beforedoing work in a confined space.

EquipmentThe equipment for work in a confined space has to be readily available,maintained and examined periodically with the examination recordssigned by a competent person & kept.



Other Measures



Mandatory trainingUnder section 34(4) of the Factories Act, only a competent person can certify a

confined space safe for entry. One has to undergo the “Confined Space Safety Assessor Course” in order to be certified as competent in assessing confined spacessafe for entry.

Under the Factories (Safety Training Courses) Order:

♦ Any worker who is carrying out work in manholes or confined spaces in buildingand engineering construction worksites must attend the Safety Orientation

Course (Manhole).♦ Any person who is appointed as a manhole supervisor to supervise work carried

out in manholes or confined spaces in building and engineering constructionworksites must attend the Safety Instruction Course (Manhole).

Entry Permit An entry permit should include the following:

Purpose Reason(s) why work needs to be in the confined space

Date & time Start and end time of permit Validity of permit Length of permit in effect

Location Confined space site needs to be indicated clearly Permit has to be placed outside confined space to let

others know that work is in progress

Atmospheric testing& interpretation of

results

No hazardous atmosphere in the confined space. Oxygen levels are between 19.5% and 23.5%. Concentrations of flammables are < 10% LEL.

Safety equipment

Gas testing equipment Ventilation system (mechanical blower + duct) Breathing apparatus Personal protective gear Harnesses and ropes

Material Safety Data Sheets (MSDS) Lighting Retrieval system (for emergency use) Reviving apparatus First aid box

Other Measures

R O ti Pl



Rescue Operation PlanRescue personnel have to be designated and assigned. These rescue personnelmust be trained in rescue operation including first aid, proper use of PPE and other

equipment like retrieval systems, ventilation systems etc.

Drills have to be conducted at least once a year and the records of drills conductedhave to be documented and kept.

PREVENTIVE MAINTENANCERegular preventive maintenance should be carried out on all plant, machinery andequipment used in the treatment plants. This will help to prevent any failure of theequipment due to a lack of maintenance or repair, which can result in unsafesituations.

The plant should establish a maintenance programme to ensure that the mechanicalintegrity of critical plant equipment is maintained. The programme should include but

should not be limited to the following:

Programmes to Establish

♦ An appropriate inspection programme to monitor the condition of the equipmentand machinery on a continuous basis, should be established.

♦ A corrosion control programme to maintain the integrity of critical equipment andmachinery and piping systems, should be established.

♦

Development and documentation of work practices and maintenance proceduresshould take into consideration the safety and health exposure of personnel to thework operations and the associated risks to the environment during maintenancework.

The work practices and maintenance procedures should incorporate safetyprecautionary measures such as Lockout/Tagout System and Permit-to-WorkSystems. Supplementary or special work procedures, which may include job safety

or risk analysis, should be included when undertaking high-risk work activities.

♦ Procedure or system to ensure that materials used in the maintenance of criticalequipment continues to meet design specifications. Any changes in material shallbe appropriately reviewed before use (such as consideration through a

Other Measures

C t l S t f C iti l S f t D i



Control System for Critical Safety Devices A control system to ensure that critical safety devices, which control or monitor thesafety of process equipment operation (such as safety alarms, control and shutdown

equipment), are tested and maintained periodically should be established.

The types of equipment, instruments or systems that may be considered as safetycritical devices may include, but may not be limited to the following:

♦ pressure relieving devices such as safety valves

♦ vacuum relieving devices

♦ shutdown systems such as automatic trips, cut-ins and cut-outs

♦ high priority alarms♦ compressor anti-surge systems

♦ pump low-flow recycle loop

♦ detectors and alarms for accidental release of harmful and hazardous substancesand fires

♦ critical temperature, pressure and level cut-out devices

The control system may include, but not limited to the following list:

♦ identification of the list of safety critical devices;

♦ designation of responsibility and accountability for the approved list of safetycritical devices;

♦ the frequency and scope of testing of the devices;

♦ procedure for testing, acceptable limits and criteria for passing the test. (Theprocedure may also include criteria for special testing exemption by designated

management.)♦ relevant training of personnel involved in the testing and maintenance of the

devices; and

♦ documentation of test records which shall be reported to the responsible personfor acknowledgement and implementation of corrective action.

MANAGEMENT OF CHANGEFor any changes to the design, operation or maintenance of plant machinery andequipment, a programme should be implemented to record, schedule, address andmonitor hazards that may be introduced by the changes.

Other Measures

♦ Technical basis of the change



♦ Technical basis of the change

♦ Impact of change on safety and health

♦ Modifications to operating procedures

♦ Time period for change

♦ Authorisation requirements

After the change has been made, affected employees should be informed andtrained. Also, process safety information and operating procedures have to beupdated according to the changes made.

EMERGENCY PREPAREDNESS & RESPONSEEmergency planning is a backup to the preventive measures for the control of chemical hazards. Occupiers of factories where hazardous chemicals are usedshould conduct a hazard study as illustrated in Chapter 4. They should assess thefollowing:

♦ what could happen to cause an emergency situation (CAUSE)

♦ what dangers could arise to people as a result of these emergencies(CONSEQUENCE) and

♦ how these could be mitigated by planned remedial and rescue measures(CONTROL)

Emergency Plan A written emergency response plan should be established to mitigate consequencesarising from emergency situations. Procedures should be established to: identify emergency situations and their impacts; implement emergency response plans for each level of the organisation, with

clear scope, roles and responsibilities; and maintain an up-to-date emergency response plan.

The emergency response plan should be documented and effectivelycommunicated. The plan should include the following:

♦ establishment of the Emergency Team(s) and its duties and responsibilities;

i t t f th E S i t d t h h ld d th

Other Measures



Effective first aid programmes should be established to provide first-aid andemergency treatment to victims of an accident. This would include provision of

adequate first aid facilities and trained first aiders.

First Aid ProceduresThe standard emergency treatments of victims involved in somecommon chemical accidents are as follows:

♦

Splashes on the skin remove contaminated clothing and flush with water for atleast 10 minutes

get medical help

♦ Splashes in the eye flush the eyes with water for several minutes seek medical treatment

♦ Inhalation of gases or vapours remove casualty to a safe area apply cardiac pulmonary resuscitation (CPR) if breathing

has stopped send for medical aid immediately

♦

Ingestion of poisonous chemicals wash the mouth with water do not induce vomiting remove victim to hospital

In all cases of splashes, inhalation and ingestion of toxic or corrosive chemicals,information on the chemicals could be found in the MSDS. Thus, the MSDS for thechemicals should be available for first aiders and medical personnel to apply proper

treatment.

References

6 REFERENCES



6. REFERENCES

1. Charles A. Wentz (1995)

Hazardous Waste Management ; McGraw-Hill, Inc.

2. Metcalf and Eddy, Inc. (1991)Wastewater Engineering – Treatment, Disposal and Reuse; McGraw-Hill, Inc.

3. Office of Environment, Safety and Health and Office of EnvironmentalManagement, U.S. Department of Energy (June 1996)

Handbook for Occupational Safety and Health During Hazardous Waste Activities.

4. National Institute for Occupational Safety and Health (NIOSH), OccupationalSafety and Health Administration (OSHA), U.S. Coast Guard (USCG) and U.S.Environmental Protection Agency (EPA) (October 1985)Occupational Safety and Health Guidance Manual for Hazardous Waste Site Activities.

5. Environmental Protection Department, Hong Kong (November 1999)Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes.

6. Singapore Standard CP 74:1998, Code of Practice for Selection, Use and Maintenance of Respiratory Protective Devices; Singapore Productivity andStandards Board.

7. Singapore Standard CP27:1999, Code of Practice for Factory Layout - Safety,Health and welfare Considerations; Singapore Productivity and StandardsBoard.

8. Singapore Standard CP50:1997, Code of Practice for Safety in Welding and Cutting (and other Operations involving the Use of Heat); SingaporeProductivity and Standards Board.

9. Singapore Standard CP 84:2000, Code of Practice for Entry into and SafeWorking in Confined Spaces; Singapore Productivity and Standards Board.

10. Merv Fingas (2001)

Other Measures

14. Oil and Petrochemical Industry Technical & Safety Committee and the Ministry



14. Oil and Petrochemical Industry Technical & Safety Committee and the Ministryof Manpower (2001)Code of Practice on Safety Management System for the Chemical Industry.

15. NIOSH Pocket Guide to Chemical Hazardshttp://www.cdc.gov/niosh/npg/npg.html

16. Factories Acthttp://statutes.agc.gov.sg/

Appendix 1

Links



The National Environment Agency (NEA)

http://www.nea.gov.sg/

The Singapore Civil Defence Force (SCDF)http://www.scdf.gov.sg

SPRING Singapore (Standards, Productivity and Innovation Board)http://www.spring.gov.sg

Appendix 2

TYPE OF TESTS TO BE CONDUCTED FOR HAZARDS IDENTIFIED


http://www.scdf.gov.sg/

http://www.spring.gov.sg/

http://www.spring.gov.sg/

http://www.scdf.gov.sg/




Type of test conducted

Chemical

Pre-

employmentexamination

Periodicexamination Sampling details

Min

Vol(ml)

Recommended

safe level(BTLV)

Instruction toworkers for

collection of specimen

Indications for suspension from

continuedexposure

Arsenic(As)

a) Urine As a) Urine As ♦ EMU

♦ clean sterilebottle (Resultscorrected to SG= 1.016)

35 300 µg/l Abstain fromseafood for 3days beforetest

♦ U-As> 300 µg/l

♦ Cancer

♦ Pregnancy

♦ Abnormal liver function test

b) Liver function test:Bil, AST, ALT, SAP,GGT

c) Full-sized

Chest X-ray(CXR)

♦ plain tube 5 Abstain fromalcohol for atleast 2 weeks

Benzene a)Urinephenol

b)FBC &peripheralblood film

a)Urinephenol

b)FBC &peripheralblood film

♦ ESU mid-week

♦ clean sterilebottle (Resultscorrected to SG= 1.016)

♦ EDTA bottle

3

20

50 mg/l Not to takeaspirin atleast 3 daysbefore test

♦ U phenol > 50mg/l

♦ Anemia

♦ Leukemia

Appendix 2

Type of test conductedMin Recommended

Instruction to Indications for



ChemicalPre-

employment

examination

Periodic

examination

Sampling detailsMinVol

(ml)

Recommendedsafe level

(BTLV)

workers for collection of

specimen

suspension fromcontinued

exposureCadmium(Cd)

a)Blood Cd

b)Urine B2

microglobulin

a)Blood Cd

b)Urine B2

microglobulin

♦ venous blood

♦ heparinishedtube

♦ plain bottle

♦ accept sampleonly if pH>5.6

♦ Specimens toreach laboratorywithin 2 hrs.

3

50

10 µg/l

<290 µg/l

Collectspecimen 2hrs after

drinking 15ml Mist. Pot.Cit.

♦ B Cd > 10 µg/l(twice)

♦ U Cd > 10 µg/l(twice)

♦ U B2

microglobulin >

290 µg/l♦ Renal

dysfunction

♦ Abnormal lungfunction

♦ Lung cancer

OrganicLead(Pb)

a)Urine Pb a)Urine Pb

♦ EMU, end of

workweek♦ clean sterile

bottle

♦ Intermittentexposure:collect beforeand after job

♦ (Results

corrected to SG-1.016)

30 <150 µg/l ♦ U Pb >150 µg/l

Appendix 2

Type of test conductedMin Recommended

Instruction to Indications for



ChemicalPre-

employment

examination

Periodic

examination


(ml)


(BTLV)


specimen


exposureInorganicLead

a)Blood Pb a)Blood Pb ♦ venous blood

♦ heparinisedcontainers

3 Male:

50µg/dl

Female30µg/dl

♦ Males: > 50µg/dl

♦ Females: >

30µg/dl

♦ Significantanemia

♦ Pregnancy

♦ Nursing mothers

b)Hb b)Hb ♦ EDTA bottle 2

Manganese(Mn)

a)Urine Mn a)Urine Mn ♦ EMU

♦ clean sterilebottle

♦ (Results

corrected toSG=1.016)

35 50 µg/l ♦ U Mn > 50 µg/l(twice)

♦ Evidence of pneumonia,

behavioural or neurologicalchanges

InorganicMercury(Hg)

a)Urine Hg a) Urine Hg ♦ EMU

♦ clean sterilebottle (Resultscorrected toSG=1.016)

35 50 µg/l ♦ U Hg > 50 µg/l

♦ Abnormal kidneyfunction

Appendix 2


PMin Recommended

Instruction tok f

Indications for i f



ChemicalPre-

employment

examination

Periodic

examination


(ml)


(BTLV)


specimen


exposureNickel (Ni) a) Urine Ni a) Urine Ni ♦ ESU mid-week

♦ clean sterilebottle (Resultscorrected toSG=1.016 or urinary

creatinine)

35 50 µg/l ♦ U Ni > 50 µg/l

Organo-phosphates

a) rbccholines-terase

b) Plasmacholines-terase

a) rbccholines-terase

♦ venous blood

♦ heparinisedtube

♦ sendimmediately tolab (keepchilled)

5

5

70% of baselineor lower limit(LL) of lab

normal

♦ rbccholinesterase <50% of baselineor LL of labnormal

♦ rbccholinesterase

between 50 –70% of baselinewith fall of > 10%in repeat results

Perchloro-ethylene

(PCE)

a) UTCA a) UTCA ♦ ESU mid-week

♦ clean sterile

bottle (Resultscorrected toSG=1.016 or urinarycreatinine)

35 7 mg/lor

7 mg/gcreatinine

Abstain fromalcohol for at

least oneweek

♦ U TCA> 7mg/l(twice)

♦ Persistentlyabnormal liver function test

Appendix 2


PreMin Recommended





ChemicalPre-

employment

examination

Periodic

examination

Sampling details Vol

(ml)

safe level

(BTLV)


specimen


exposureb) Liver function test:Bil, AST, ALT, SAP,GGT


Silica a) Full-sized

CXR

a) Full-sized

CXR

♦ Worker < 35 yrs

with symptomaticsilicosis

♦ Tuberculosis andother cardio-respiratorydiseases

Tar, Pitch,Bitumen

andCreosote

Clinicalexamination

only

Clinicalexamination

only

♦ Pre-malignant or malignant

neoplasms of skin or lung

Toluene a)UrineHippuric acid

OR

b) Bloodtoluene

a)UrineHippuric acid

OR

b) Bloodtoluene

♦ ESU mid-week

♦ clean sterilebottle (Resultscorrected toSG=1.016 or

urinarycreatinine)

♦ Lithiumheparinisedtube

35

5

1.6 g/gcreatinine or g/l

0.05 mg/L (prior to last shift of

workweek)

♦ U hippuric acid >1.6 g/g creat or g/l

OR

♦ Blood toluene >

0.05 mg/L

♦ Persistentlyabnormal liver function testresults

Appendix 2


PreMin Recommended





ChemicalPre-

employment

examination

Periodic

examination

Sampling details Vol

(ml)

safe level

(BTLV)


specimen


exposureTrichloro-ethylene(TCE)

a)Urinetrichloro-acetic acid(UTCA)

a)Urinetrichloro-acetic acid(UTCA)

♦ ESU mid-week

♦ clean sterilebottle (Resultscorrected toSG=1.016 or urinary

creatinine)

35 100 mg/l or mg/g

creatinine

50 mg/l or mg/gcreatinine if

mixture of TCEand PCE

(PCE < half PEL)

Abstain fromalcohol for atleast oneweek

♦ U TCA > 100mg/l (twice)

♦ Persistentlyabnormal liver function testresults

♦ Suspect allergy:fever, skin rashand jaundice

b) Liver function test:Bil, AST, ALT, SAP,

GGT


Xylene a)Urinemethylhippuric acid

a)Urinemethylhippuric acid

♦ ESU mid-week

♦ clean sterilebottle (Resultscorrected toSG=1.016)

35 1.5 g/gcreat or g/l

♦ U methyl-hippuric acid >1.5 g/g creat or g/l

♦ Persistently

abnormal liver function testresults

Appendix 3

N.B. Use separate summary reports for different hazards



SUMMARY OF MEDICAL EXAMINATIONS

Company: ______________________________________Tel:______________

Address of Company: _____________________________Fax:_____________

Hazard: _________ Total no. of exposed employees: ______________

No. of employees examined: ______________________________

No. with normal results : ______________________________

No. with abnormal results : ______________________________

a. Occupational : ______________________________ b. Not Occupational : ______________________________

No. of employees recommended for suspension:__________________

The laboratory conducting the analysis *does/does not participate in the following proficiency testing scheme for the relevant chemical: *DSS/NEQAS/RobensInstitute/Danish EQAS/NIOSH/ Others: (Specify)______________________________________________ ________

I confirm that the information given above is correct and accurate. All workers werecounselled on the importance of wearing respirators and gloves when exposed totoluene.

Details of the employees with abnormal results are attached.

Name of Doctor: _______________________DFD Reg. No (if applicable) :__________

Name & Address of Practice: _______________________________________________

Tel No: Fax No:

Appendix 3

N.B. If there are any abnormal test results, to submit list to Occupational Safety andHealth Division, Ministry of Manpower



Health Division, Ministry of Manpower

EMPLOYEES WITH ABNORMAL RESULTS

No NameNRIC /

FINNo.

SexDate of Exam.

ClinicalFindings*

DiagnosisActionstaken

Appendix 4

N.B. Use separate registers for different hazards



REGISTER OF PERSONS EMPLOYEDIN WORK INVOLVING EXPOSURE TO ____________ (hazard)

Name of Factory:________________________________________________________________________

Address of Factory:________________________________________________________________________

______________________________________________________________________________

Date of Test: ______________________

Name of Laboratory conducting test: ____________________________________________

To be completed by Employer

PLEASE WRITE IN BLOCK LETTERS OR USE SOFTCOPY

To becompleted

by

laboratory/ doctor

Work involvingexposure to

hazardName NRIC/FIN

SexDate of

BirthRace

Dept /Section Date

startedDate

stopped

Results of blood or urine testconducted

Appendix 5

AANN EEXXAAMMPPLLEE OOFF AA WWAASSTTEE TTRREEAATTMMEENNTT LLOOGG



AANN EEXXAAMMPPLLEE OOFF AA WWAASSTTEE TTRREEAATTMMEENNTT LLOOGG

DDaattee SSttaar r tt TTiimmee TTyyppee oof f WWaassttee

TTr r eeaatteedd

TTr r eeaattmmeennttMMeetthhoodd

TTr r eeaattmmeennttCChheemmiiccaallss

UUsseeddOOppeer r aattoor r EEnndd TTiimmee

Appendix 6

LLEEGGIISSLLAATTIIOONN OONN HHAAZZAARRDDOOUUSS SSUUBBSSTTAANNCCEESS IINN FFAACCTTOORRIIEESS



In Singapore, the law relating to the health, safety and welfare of personsemployed in factories is the Factories Act. It is administered by the Ministry of Manpower.

The Factories Act has a number of sections dealing with the control andprevention of chemical hazards. Summarized below are the importantprovisions relating to the control of flammable, explosive and toxic substancesin factories.

Flammable SubstancesSection 35 of the Factories Act requires precautions to be taken againstexplosion from any flammable dust, gas, vapour or substance that mayescape into any workplace. The precautions include removal or prevention of accumulation of flammable substances and exclusion of possible sources of

ignition.

This section also requires that flammable or explosive substances in anyplant, tank or vessel must be removed or rendered non-flammable or non-explosive before carrying out any hot work on such plant, tank or vessel.

Section 46(1) stipulates that practical steps must be taken to keep sources of heat or ignition separate from flammable substances or any process whichmay give rise to any flammable gas or vapour.

Airborne ContaminantsInhalation of airborne contaminants eg toxic gases, vapours, dusts and fumesis the most common path of exposure to chemicals in workplaces. Control of such contaminants is required under section 59 of the Factories Act.

This section requires that all practicable measures must be taken to protectemployed persons against inhalation of toxic airborne contaminants and toprevent their accumulation in any workplace. The measures to be takeninclude one or more of the following where appropriate:-



Appendix 6

• take effective measures to prevent the liberation of harmful substancesand for the protection of workers against inhalation, skin absorption or i ti f th b t d



ingestion of the substances; and

• take preventive measures for the protection of workers from harmfulradiation.

Meals in Certain Dangerous TradesSection 61 states that there should be no taking of food or drinks in any roomwhere toxic or injurious dust or fume is liberated. Suitable facilities must bemade available to enable workers to take their meals elsewhere in the factory.

Protective Clothing and AppliancesSection 62(1) of the Factories Act stipulates that suitable protective clothingand appliances including where necessary, suitable gloves and respiratorsmust be provided and maintained for the use of workers who are exposed toany toxic or offensive substance.

Separate Changing and Washing FacilitiesUnder section 66 of the Factories Act, the Chief Inspector may direct thefactory occupier to provide separate changing and washing facilities for persons employed in any process involving the manufacture, handling or useof toxic, injurious or offensive substances.

Permissible Exposure LevelsThe permissible exposure levels (PEL) of some 600 toxic substances arespecified in the Factories (Permissible Exposure Levels of Toxic Substances)Notification. This Notification is operative from 1 Jan 97.

PEL is the maximum time weighted average concentration in the air of a toxic

substance to which persons may be exposed without suffering from anyadverse health effects. Two types of PEL are prescribed:-

• PEL (Long Term) means the permissible exposure level over an 8-hour working day and a 40-hour working week.

Appendix 6

bitumen, creosote, silica, asbestos, trichloroethylene, perchloroethylene, lead,mercury, manganese, cadmium and arsenic or their compounds.



The objective of these examinations is to detect work related illness early andto ensure workers are fit for such work.

The examinations are specific to the type of hazards involved. The employer must arrange and pay for these examinations which must be carried out by adesignated factory doctor registered with the Chief Inspector of Factories.

Appendix 7

Emergency Treatment

1 Emergency Shower/Eyewash



1. Emergency Shower/Eyewash

Suitable facilities for quick drenching or flushing of the eyes and body mustbe provided within the work area for emergency use, especially wheretoxic or corrosive substances are used.

2. Hydrogen Fluoride (HF) BurnFor HF burns, wash the affected part thoroughly under water and applycalcium gluconate gel immediately. Remove all contaminated clothingduring washing. Cut away clothing, if necessary, to avoid injuring affectedskin. See a doctor without delay after the emergency treatment.

3. Cyanide Overexposure/PoisoningIf the patient is not breathing, give amyl nitrite inhalation and performartificial respiration (using a manual resuscitator or one-way valve) or giveoxygen.Do not perform mouth-to-mouth or mouth-to-nose resuscitation without the

use of a one-way valve as cyanide is present in the breath of the patient.In addition, it is also not recommended to use a two-way mouth-piece for the resuscitation.Remove all contaminated clothing immediately and wash off all cyanide onthe skin thoroughly since cyanide can be absorbed through unbroken skin.

4. Hydrogen Sulphide and Carbon Monoxide Overexposure/PoisoningIf the patient is not breathing, immediately perform artificial respiration or

give oxygen till help arrives.

Appendix 8

Specific Health Hazards of Common Chemicals within the Toxic Industrial Waste Treatment Industry



Chemical Health Hazards Target Organs Incompatibles & Reactivities

Hydrochloric acid

Irritation nose, throat, larynx;cough, choking; dermatitis;solution: eye, skin burns; liquid:frostbite; in animals: laryngealspasm; pulmonary edema

Eyes, skin, respiratory system Hydroxides, amines, alkalis,copper, brass, zinc[Note: Hydrochloric acid is highlycorrosive to most metals.]

Sulphuric acid

Irritation eyes, skin, nose, throat;

pulmonary edema, bronchitis;emphysema; conjunctivitis;stomatis; dental erosion; eye, skinburns; dermatitis

Eyes, skin, respiratory system,

teeth

Organic materials, chlorates,

carbides, fulminates, water,powdered metals[Note: Reacts violently with waterwith evolution of heat. Corrosiveto metals.]

Hydrofluoric Acid

Irritation eyes, skin, nose, throat;pulmonary edema; eye, skin

burns; rhinitis; bronchitis; bonechanges

Eyes, skin, respiratory system,bones

Metals, water or steam[Note: Corrosive to metals. Will

attack glass and concrete.]

Sodium hydroxide

Irritation eyes, skin, mucousmembrane; pneumonitis; eye,skin burns; temporary loss of hair

Eyes, skin, respiratory system Water; acids; flammable liquids;organic halogens; metals such asaluminum, tin & zinc;nitromethane[Note: Corrosive to metals.]

Appendix 8


I it ti i t t Bl d i t t li C b tibl i th



Chromic acid

Irritation respiratory system;

nasal septum perforation; liver,kidney damage; leukocytosis(increased blood leukocytes),leukopenia (reduced bloodleukocytes), eosinophilia; eyeinjury, conjunctivitis; skin ulcer,sensitization dermatitis; [potential

occupational carcinogen]

Blood, respiratory system, liver,

kidneys, eyes, skin

Cancer Site [lung cancer]

Combustible, organic, or other

readily oxidizable materials(paper, wood, sulfur, aluminum,plastics, etc.); corrosive to metals

Hydrogen sulphide(H2S)

Irritation eyes, respiratorysystem; apnea, coma,convulsions; conjunctivitis, eyepain, lacrimation (discharge of tears), photophobia (abnormalvisual intolerance to light),

corneal vesiculation; dizziness,headache, lassitude (weakness,exhaustion), irritability, insomnia;gastrointestinal disturbance;liquid: frostbite

Eyes, respiratory system, centralnervous system

Strong oxidizers, strong nitricacid, metals

Hydrogen cyanide(HCN)

Asphyxia; lassitude (weakness,exhaustion), headache, confusion;

nausea, vomiting; increased rateand depth of respiration orrespiration slow and gasping;thyroid, blood changes

central nervous system,cardiovascular system, thyroid,

blood

Amines, oxidizers, acids, sodiumhydroxide, calcium hydroxide,

sodium carbonate, caustics,ammonia[Note: Can polymerize at 122-140°F.]



Appendix 8


Irritation eyes skin; headache Eyes skin respiratory system Strong caustics & alkalis;



Trichloroethylene(TCE)

Irritation eyes, skin; headache,

visual disturbance, lassitude(weakness, exhaustion), dizziness,tremor, drowsiness, nausea,vomiting; dermatitis; cardiacarrhythmias, paresthesia; liverinjury; [potential occupationalcarcinogen]

Eyes, skin, respiratory system,

heart, liver, kidneys, centralnervous system

Cancer Site [in animals: liver & kidney cancer]

Strong caustics & alkalis;

chemically-active metals (such asbarium, lithium, sodium,magnesium, titanium & beryllium)

Perchloroethylene(Tetrachloroethyleneor PCE)

Irritation eyes, skin, nose, throat,respiratory system; nausea; flushface, neck; dizziness,incoordination; headache,drowsiness; skin erythema (skinredness); liver damage; [potentialoccupational carcinogen]

Eyes, skin, respiratory system,liver, kidneys, central nervoussystem

Cancer Site [in animals: livertumors]

Strong oxidizers; chemically-activemetals such as lithium, beryllium& barium; caustic soda; sodiumhydroxide; potash

Toluene

Irritation eyes, nose; lassitude(weakness, exhaustion),confusion, euphoria, dizziness,headache; dilated pupils,lacrimation (discharge of tears);anxiety, muscle fatigue, insomnia;paresthesia; dermatitis; liver,

kidney damage

Eyes, skin, respiratory system,central nervous system, liver,kidneys

Strong oxidizers

Appendix 8


Dizziness nausea vomiting; central nervous system liver Chemically-active metals such as



Methylene chloride(MC)

Dizziness, nausea, vomiting;

visual disturbance, stagger,slurred speech, convulsions,coma; liver, kidney damage;liquid: frostbite; reproductive,teratogenic effects; [potentialoccupational carcinogen]

central nervous system, liver,

kidneys, reproductive system

Cancer Site [in animals: lung,kidney & forestomach tumors]

Chemically active metals such as

potassium, powdered aluminum,zinc & magnesium; water[Note: Reacts with water(hydrolyzes) to form hydrochloricacid.]

♦ For more details on incompatible chemicals, please also refer to the table on “Incompatible & Pyrophoric Chemicals” in the

Ministry of Manpower’s guidelines on “Prevention and Control of Chemical Hazards” .

osh mom guidelines on toxic industrial waste treatment

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