Silicosis is a pulmonary disease caused by inhaling respirable silica dust, which is capable of inducing fibrosis of the lung parenchyma and may also affect the pleura. In some countries where pulmonary tuberculosis is rife, such as Thailand, interaction between the dust-induced disease and the tubercular infection worsens the harmful effects of silica dust.

Thailand, a Southeast Asian country, has experienced rapid economic growth during the past decade, as well as a widespread increase in industrialization. These developments have sparked much construction work, and the numbers of workers employed in stone quarrying, tunnelling, foundries, masonry, the manufacture of construction materials, sandblasting, etc. have risen (Table 1).

Table 1. Number of factories and number of workers at risk of silicosis.

Source: Department of Industrial Plants, Ministry of Industry

The information needed to control silicosis effectively is available, but its application has been very limited. In stone quarrying, for instance, engineering control measures are both difficult and costly. The wet method of quarrying stone has been introduced, but this is not a practical method in areas where water is scarce. The spread of industrialisation has thus led to increases in the number of silicosis cases being reported.

In 1991, the Division of Occupational Health within the Department of Health of Thailand's Ministry of Public Health conducted a pilot project to launch the Silicosis Monitoring Programme. Five enterprises, one mine (90 workers) and four glass-making plants (110 workers), were surveyed for the pilot project. This study revealed 17 cases of silicosis in the mine, but no case in the glass-making plants. The cases of silicosis detected were caused by the high levels of silica dust and the poor personal protection in the mine. The Silicosis Monitoring Programme has since been expanded to cover more stone quarries and stone mortar manufacturing plants. The activities of the Silicosis Monitoring Programme for 1993 to 1995 are shown in Table 2.

Table 2. Silicosis Monitoring Programme 1993-1995. 

The findings of the Silicosis Monitoring Programme are disturbing to all concerned; government, the private sector, employers and workers. The Ministry of Industry, the Ministry of Science, Technology, and Environment and the engineering experts at the universities initiated much research and development work in order to devise effective engineering control measures appropriate for the plants and branches in question and at a reasonable expense. The Ministry of Public Health has conducted specific studies, aiming to design an appropriate mask that would be cheap and easily available to workers exposed to silica dust. Through various media, including television programmes, radio broadcasts, group education events and the distribution of pamphlets, the public and private sectors are together carrying out a health education programme to raise awareness and to foster good health practices among employers and workers alike. Another most important aspect that cannot be overlooked is law enforcement, which is under the direction of the Ministry of Industry, the Ministry of Labour and Social Welfare, and the local authorities.

Thailand is currently in the midst of an economic recession and most plants have slowed down their work. Now is thus a good time to strengthen the Silicosis Control Programme, with the cooperation of all involved parties.

We believe that continuation of these intense efforts, together with the development of occupational health services as recommended by WHO and ILO, will enable Thailand to eliminate silicosis by the end of the year 2000.

Wilawan Juengprasert
Department of Health
Ministry of Public Health
Nonthaburi
THAILAND

Updated by PAP/SUT/TRS. Approved by BKL. Last updated on 12 February 2001

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