CHEMICAL HAZARD AND PREVENTION

FIRDAUS ALI

BSc (Health and Safety), Curtin University, Perth Australia

Objectives of this session Understand the key definitions and fundamental

concepts of chemical hazards

Identification of chemical hazard and route of exposure

Describe the worksite assessment process

Identify the hierarchy of control measures

Spot the hazard

Key DefinitionsHazardA situation that poses a level of threat

to life, health, property or environment

RiskThe chance of something happening

that will have an impact on life, health, property or environment

(AS/NZS 4360:2004)

Exposure Defined as the contact over time

and space between a person and one or more biological, chemical or physical agents based on frequency, magnitude and duration

(US Nuclear Regulatory Commission, 1991).

ToxicologyDefined as the study

of adverse, and potentially adverse, effects of chemicals which have, or may have, the capacity to cause injury to living organisms.

"Dosis facit venenum" - The Dose Makes the Poison

All substances are poisons; there is none which is not a poison. The right dose differentiates a poison…." Paracelsus (1493-1541)

Dose

The dose of a hazardous substance is generally expressed with the following equation:

Dose = concentration (level) x duration of exposure.

This is a fundamental principle on which occupational exposure limits (OELs) are based

ToxicityRefers to its capacity to

injure if it reaches a susceptible site on the body. Whether ill-effects will occur depends on:

The properties of the chemical

The dose (amount of chemical acting on the body)

The susceptibility or resistance of the exposed individual

The route by which the substance enters the body

Identification of Chemical HazardSubstances which can be inhaled, or are

respirable, include gases, vapours and aerosols, may be defined as follows:

GASES: substances which normally exist in gaseous form at standard pressure and temperature

VAPOURS: the gaseous form of substances normally liquid at standard pressure and temperature

AEROSOLS: suspensions of variable size particles capable of remaining airborne

Dusts – caused by mechanical abrasion or fragmentation of solids

Fumes – produced by combustion, sublimation or condensation of volatile solids.

Smokes – suspension of solid particles produced by incomplete combustion of organic materials

Mists – airborne droplets usually formed by condensation of vapours but may be produced by atomisation of a liquid

Chemicals That Present Hazard or Risk◦Flammability: catch fire readily;

gasoline◦Reactivity: unstable and may

explode or create toxic fumes when mixed with water; explosives, concentrated sulfuric acid

◦Toxicity: injurious to health; pesticides, chlorine

Material Safety Datasheets

A document containing important information about a hazardous chemical (which may be hazardous substance and/or dangerous goods) and must state:

a hazardous substance's product namethe chemical and generic name of certain

ingredientsthe chemical and physical properties of

the hazardous substancehealth hazard informationprecautions for safe use and handling

Available at:http://www.ilo.org

International Version published by the WHO and European Union

Chemical Groups

Available at:http://www.cdc.gov/niosh

Safety Label

Legislation on Chemical SafetyPoison Act, 1956Disaster Management Order,

2006Workplace Safety and Health

Order, 2009

Available at:http://www.agc.gov.bn

Route of Exposure

The Respiratory SystemA large range of vapours and gases, dusts,

fumes can enter the respiratory tract through inhalation

Odours - danger lies in using chemicals which have no odour, or where toxicity occurs before odour is detected. People who have had a long term exposure to a chemical tend to ignore the smell

Dusts - Many dust particles are small enough to enter the alveoli air pockets where they can cause damage

The SkinThe protective properties of the skin can be

reduced by exposure to chemicals such as degreasers, detergents, and solvents

Chemical exposure can result in dryness, splitting and cracking and damage to the skin surface

Sensitivity to chemicals can cause allergic reactions - in rare circumstances can cause death

The EyesSome chemicals have very strong

vapours that can cause acute discomfort to the eyes.

Exposure to these types of fumes can cause permanent damage to the eyes.

Care must be taken to protect from splashes as well as fumes

The Gastro - Intestinal TractUsually due to poor housekeeping,

dusty environments and the close proximity of toxic airborne substances to eating facilities.

Poor hygiene practices (not washing hands before eating & not wearing gloves when dealing with chemical) can also prove hazardous

Potential Chronic Health ProblemsOccupational Asthma

(Glutaraldehyde)Carcinogen (Ethylene oxide and

Cyctotoxic Drugs)Kidney Failure (Lead fumes)Lung Fibrosis (Diesel) ?

WORKSITE ASSESSMENT PROCESS

Direct health indicators (workercomplaints, illness statistics, biological orradiological signs before symptoms occur)

Previous experience and information(MSDS, material inputs, the process, thepattern of exposure, work procedures)

Walk-through survey (5 P’s; People, Premises, Process, Product, Personal Protective Equipment)

Specific Site

Specific Task

Risk Assessment

Systematic process for describing and quantifying the risks associated with hazards including substances, processes, action or events.

The overall process of risk identification, risk analysis and risk evaluation (AS/NZS 4360:2004).

Hazard Risk & Health Consequence

Poor lifting techniques of patients and equipment (over 20 kgs)

Musculoskeletal Injuries-Lumber Disc Protrusion-Back Injury

Improper recapping of needles

Needlestick Injuries-Bloodborne diseases (HIV, Hepatitis B)

Chemical handling on Glutaraldehyde (Cidex) for disinfecting endoscopy and operating theatre instruments

Respiratory problems-Occupational Asthma-Contact Dermatitis

Chemical handling on Glutaraldehyde (Cidex) for disinfecting endoscopy and operating theatre instruments

Exposure Occupational Exposure Limits (OELs)

Risk

8 hours

PPE in place (hand gloves, face guard, face mask)

Fume window closed

<0.2ppm Low

8 hours

PPE not in place

Fume window open

>0.2ppm High

Control measures

5 steps of hierarchy of control measures

Elimination (Remove)Substitution (Replace)Engineering Control

(Remodel/Renovate)Administrative/Procedural Control

(Reinforce)Personal Protective Equipment

(last Resort)

EliminationDepends!-Detrimental effect on human body-Demand of the product

Substitution-Replace with a less hazardous substance

Engineering Control-Fume Cupboard (Grading for different types of chemical handling/performance)-Ventilated room with back vent

Administrative/Procedural Control-Education and Training-Legislation -Standard Safety Procedure (Chemical Handling)-MSDS-Incident Report-Regular medical checkup

Personal Protective EquipmentDifferent types of chemical have different use on each equipment-Hand Gloves-Face Guard/Mask-Safety Apron/Safety Suit-Rubber Boots-Helmet ?

SCENARIOYou as an Occupational Health Nurse have been

advised to investigate an incident in the endoscopy unit. It was reported that 10 healthcare workers have been suffering from acute exacerbation of asthma for 3 days. It was later identified that all affected HCWs were handling Glutaraldehyde (Cidex) while disinfecting endoscopic instruments.

(a) Describe how would you perform a worksite assessment.

(b) Using the hierarchy of control measures, provide

recommendation in order to minimise the health impact of Glutaraldehyde (Cidex)

WORKSITE ASSESSMENT

Walk through Survey5 P’s (People, Premise, Process and

Product, Personal Protective Equipment)

Specific Site

Specific Task(the pattern of exposure, work

procedures)

SubstitutionReplace Glutaraldehyde with a less toxic substance.

Engineering ControlsProvide local exhaust ventilation such as laboratory hood, large enough to contain the Glutaraldehyde immersion system and an equipment washing and rising sink at the source. The design should include a face velocity at the hood with the airflow directed toward the back of the hood away from the operator’s breathing zone. This system will require an appropriate amount of filtered and tempered replacement air in order to work properly

Increase general room ventilation. This solution is generally ineffective in controlling exposure due to short-term tasks such as equipment cleaning or solution changes that may generate a high concentration contaminant quickly

Provide buckets and other containers that are shaped to minimise the surface area of the liquid.

Modify facility design to limit traffic or potential exposure to individuals who are not involved with the disinfection process. Exposure to Glutaraldehyde solutions in confined spaces should be avoided

Administrative controlsReviewing work practices periodically in all areas

where Glutaraldehyde is used in order to prevent overexposure. Communicate with other areas of the hospital setting that use Glutaraldehyde such as surgical department, emergency rooms, intensive care unit or central sterile supply department

Training and educating new and current healthcare workers regarding safe work practices is essential in reducing chemical exposure. All new and current healthcare workers should be instructed about the potential hazards associated with Glutaraldehyde, proper use of protective clothing, safe work practices, avoidance of exposure in a confined space and personal hygiene concerns. This would include education regarding signs and symptoms associated with overexposure to Glutaraldehyde

Personal protective equipmentA written procedure detailing the type of

clothing and the proper use of protective clothing should be provided to healthcare workers involved in maintenance and disinfecting medical instruments.

Proper gloves wear such as butyl rubber, polyurethane or Viton could be use

Respirators or face mask are necessary when the exposure to a chemical exceeds 0.1ppm. Nevertheless, this should be known not as a primary control since the availability of engineering control and substitution of chemical. Yet, this can still be use in non routine maintenance or emergencies (NIOSH, 2005).

Further Informationhttp://www.worksafe.vic.gov.au

http://www.westcoastdhb.org.nz

http://www.ilo.org

http://www.cdc.gov/niosh

http://toxnet.nlm.nih.gov/