FACT SHEET - Occupational Health : Vol. 1 No. 10 July 1998

Occupational Lung Diseases Dr.Sasitorn Taptagaporn - Public Health Officer 7

Siriluck Simapornchai - Public Health Officer 7 Division of Occupational Health, Department of Health Tel : 590-4296, 590-4289

Figure1: Working condition of worker at a rock-crushing mill, one of potential health hazard of Silicosis

Silicosis (resulting from silica dust) , Asbestosis (resulting from asbestos fibers) and Byssinosis (resulting from cotton, flax and hemp) are the most common and serious of pneumoconioses. The most common occupational lung disease found in Thailand is caused by particulates, especially pneumoconioses and byssinosis.

Occupational lung diseases result from inhalation of dust, smoke, toxic substances, microorganisms or by-products during work. The inhalation causes diseases or disorders of the respiratory system and may produce chronic pathological effects to lung tissue leading to death, depending on severity of the disease. The most common occupa-tional lung disease found in Thailand is caused by particulates, especially pneumoconioses (resulting from the accumulation of inorganic or mineral dust in the lungs and the tissue reaction to its presence) and byssinosis (resulting from cotton, flax and hemp). However, it is often difficult to estimate the full extent of the pneumoconiosis problem in Thailand. Although the national system of routine notification of occupational diseases includes pneumoconiosis, this can rarely be relied upon because of gross under-reporting.

The most common and serious sorts of pneumoconiosis are silicosis (resulting from silica dust) and asbestosis (resulting from asbestos fibers).

Silicosis

According to the silicosis monitoring program carried out by Division of Occupational Health in cooperation with Provincial Health Offices, there are about 6,712 workplaces that have risk to silicosis, and about 181,907 persons are at risk. The industries that have risk to silicosis are quarrying, sand blasting, glass industries, etc. Table 1 shows the results of silicosis monitoring program during 1993 - 1995. Division of Epidemiology, Office of the Permanent Secretary, Ministry of Public Health reported 24 silicosis cases in 1993, which is 8 times higher than cases detected in 1992 (3 cases). Those cases were found mostly in Loei (15 cases) and Lopburi provinces (7 cases). However, in 1994, reported silicosis cases decreased to 10. An example of potential health hazards of silicosis, working at a rock-crushing mill, is shown in Figure 1.

Asbestosis

Asbestosis is found among workers who work with asbestos, for example, in production of brake/clutch systems and roof tiles mixed with asbestos. In Thailand, asbestosis cases have been found since 1996 and there is a tendency to increase since asbestos has been imported for more than 30 years. The incubation period of the disease is more than 20 years after exposure to asbestos. There are many countries exporting asbestos, for example South Africa, Canada, China, Italy, USA, etc. In Thailand, asbestos has been mainly imported from Canada, Russia, Greece and Zimbabwe. Table 2 shows the amount of asbestos imported to Thailand during 1987 - 1991. There is an obvious increase in the amount of use to almost double within 5 years. According to the Department of Industrial Works, Ministry of Industry, in 1997 there were 1,519 employees working with asbestos in 15 factories where production covered brake and clutch systems, plastic, cement, such as pipe and roof tiles, felt, etc.

Table 1. Report of the silicosis monitoring program during 1993 - 1995.

year No. of

province

No. of invastigated workplaces

% of environmental

samplings over standard

No. of invastigated

workers

No. of workers

suspected of silicosis

No. of workers with TB

1993 38 80 100 2,601 168 -

1994 22 73 45 1,703 86 -

1995 26 92 50 1,839 186 13

Source: Division of Occupational Health, Department of Health.

Table 2. The amount of imported asbestos to Thailand since 1987 - 1991

Year Asbestos (metric tons)

1987 90,700

1988 109,933

1989 116,046

1990 124,707

1991 149,000

Source: Department of Industrial Work, Ministry of Indrustry.

Byssinosis

Byssinosis is another important disease because there are several textile factories in Thailand. The growth of textile industry occurred during the past decade. The use of cotton , flax and hemp in textile industry was about 1,200,000 metric tons/year (in 1992) where 256,000 metric tons/year were produced. In 1997, there were about 276,411 workers exposed to these fibers in 2,654 workplaces around Thailand (Table 3). Figure 2 shows working environment in a textile factory when potential health hazard of Byssinosis could be found. Even though the reported cases of the diseases are understood to be under-reported, those data could help understand the causes and trends of the occupational lung diseases in Thailand. We realize that occupational disease has chronic characteristics that take time to be properly diagnosed. However, the effective prevention and control measures should be prepared in cooperation among tri-parties, i.e., government, employers and employees.

Table 3. Working population exposed to cotton dust classified by type of industry, 1997.

Type of industry No. of factory

No. of worker

- extract oil from cotton seeds or animal fat 234 8,725

- compress or grind of plant after oil extraction 22 1,199

- ferment, carbonize, scratch, press, bake, spin, texturize, bleach or dye of cotton fiber

305 58,593

- prepare starch or weave of jean cotton 902 104,259

- make textile production used in household 119 9,133

- production of jute bag 14 16,175

- canvas production 31 1,394

- textile production and decoration 139 11,000

- clothing production 667 52,426

- production of mat and carpet 23 3,117

- production of rope (flax, hemp) 64 6,921

- production of material for mattress 58 1,784

- production of cotton fiber 76 1,685

TOTAL 2,654 276,411

Source: Department of Industrial Works, Ministry of Industry.

Implementation of prevention and control

1. Health service:

1.1 Health checks should be provided in the factory, such as pre-employment health check, periodical health check, health check after sickness or absence from work, health check before quitting the job, or health check among special groups. The frequency of periodical health checks may be every month, 3 months, 6 months or every year depending on the job characteristics. 1.2 Health promotion and disease control should be provided through health education on occupational health and safety, and by introducing health fitness and immunological programs. 1.3 First aid and medical treatment should be provided when accident or injury at work occurs with patients referred for further treatment and rehabilitation. 1.4 Setting up personal health data records covering the entire working life for follow up of occupational disease onset, and for applications for compensation or social security funds,

should be established. 1.5 Data analysis on injury types and employee absenteeism should be recorded. 1.6 Surveillance of occupa-tional lung diseases.

Prevention and control in the working environment:

2.1 The policy on health, safety and environment should be established. 2.2 Workplace construction and lay out plans should be designed including work practice for safety. 2.3 Appropriate work and rest periods should be identified. 2.4 Work processes or practices should be improved to reduce hazardous exposure, for example, spraying water to reduce dust, or providing adequate ventilation system. 2.5 Separation of hazardous jobs from other jobs. 2.6 Regular investigation of working environment with potential health hazards. 2.7 Housekeeping and sanitation. 2.8 Treatment system for liquid and solid wastes including toxic substances. 2.9 Provision of facilities for water, drinking water, bathrooms and rooms for changing clothes. As the Division of Occupa-tional Health takes responsibility for all worker s health, we have implemented control measures to develop organizations and personnel for the occupational health service which have been implemented both in the central and local areas. These include:

1. Set up an occupational health section in Provincial Health Offices, and 2. Set up an occupational medicine section in

General Hospitals.

The objectives of this implemen-tation are as follows:

1. To promote worker s health and to prevent occupational injury and disease,

2. To strengthen occupational health service to make it more accessible,

3. To develop standards and technology applied to diagnosis, prevention, treatment and rehabilitation of occupational injury and disease, and

4. To develop the capacity of concerned organizations to solve problems concerning

occupational injury and disease.

R E F E R E N C E

1. Medical Diagnosis and Surveillance of Occupational Diseases, Vol. 1, Division of Occupational Health, Dept. of Health, 1995

2. Situation and Trend of Occupational Health Problems in Thailand, Division of Occupational Health, Dept. of Health, 1996

3. Occupational Health in Developing Countries, edited by J. Jeyaratnam, Oxford University Press, 1992