Silica dust hazards in Vietnamese foundries - Asian-Pacific Newsletter on Occupational Health and Safety

4. Conclusions

4. Conclusions

Based on reported materials and pilot surveys of the Hanoi Mechanical Company and Electrical Engineering Company, the following conclusions and suggestions can be offered:

Vietnamese foundry technology is obsolescent, with many processes being performed by hand. Over the last few years, especially since 1996, many foundries have had to close for lack of orders. The survivors are operating at less than full capacity (maximum 50 per cent of designed capacity). Given production problems and limited investment capital, most foundries cannot upgrade to advanced technology. Whatever can be done to improve the working environment has already been done (for example using green sand, wetting down, etc.), but improvements are limited and inadequate. In addition, a lack of dust exhaust systems results in dust concentrations exceeding permissible limits in most foundry workstations.
In consequence, worker health has worsened. Few fall into the health categories of "excellent" or "good"; the majority are classified as "normal". Only 40 per cent of foundries have workers chest X-rayed and examined for silicosis. Foundry workers are concentrated in provinces such as Hanoi, Quang Ninh, Thai Nguyen, and Can Tho and in the ministerial sectors of Heavy Industry and Transport. The percentage of silicosis victims in Viet Nam is 9.5 per cent (among these, 2.5 per cent are compensated). Female workers often perform light jobs such as making moulds, and fewer than 2 per cent suffer from silicosis.

There are no child workers in state-owned foundries.

The figures indicate that the current incidence of silicosis is much lower than it was in 1985. Possible explanations include these:

The 1985 data were collected from factories with high-capacity foundries and large number of workers, where all the sample population had been given medical exams and chest X-rays. The 1998 data are simply statistics reported by provinces and industries. In many cases, these sources had not organized medical examinations or chest X-rays for workers exposed to silica dust.

Recent technology improvements in processes such as mould-making have much reduced dust concentrations.

Work intensity has declined due to lack of orders, with many foundries working only two or three days a week. Therefore, exposure to dust has decreased.

The pilot survey of two Hanoi foundries shows that the incidence of silicosis victims, which was 20 per cent in average 1995-1998, was twice as high as that found nationwide. Female victims among the foundry workers account for fewer than 5 per cent. The number of silicosis cases in the steel foundry was 1.5 times higher than that in the iron foundry. More than 50 per cent of crane operators were found to have silicosis. Therefore, attention should be given to these work places when considering methods of silica dust control. For example, the crane cabin should be enclosed and provided with filtered or bottled air.

To improve the working environment and, ultimately, to satisfy national standards, the basic measure is change in technological processes. Only by applying advanced technology can foundries eliminate the causes of silicosis. While the Vietnamese economy is in recession, such changes should be taken step by step. Priority should be given to the following processes:

mould-making;

cleaning of castings; and

melting.

If technological changes are not practicable, the following improvements can in the meantime reduce exposure to silica dust:

Isolate or enclose dust sources such as sand mixers, vibrating grids, and drum cleaners.

Wet down floors and mould surfaces before removing castings; axial mist fans and water spray nozzles are among the appropriate equipment;

Local dust exhaust ventilation systems play an important role in dust control for dusty processes such as mould removal, sand mixing, and steel melting. The NILP has designed hundreds of dust-control systems for industrial enterprises throughout the country. For steel processing, in particular, fume exhaust systems have been installed and operated successfully in the Duyen Hai Mechanical Company and Hai Phong Steel Mill. Scrubbers have been used as dust- and smoke-cleaning devices. This model could be widely applied for steel-melting furnaces in foundries.

Employ an OSH point system in calculating workers’ income. Income will depend how well they respect working regulations, including OSH regulations. This method also improves worker awareness of OSH issues.

Use high-quality respirators. The NILP is producing a respirator that is very effective for foundry workers. Humidifying cotton respirators, meanwhile, does help to reduce the amount of dust inhaled.

Organize training courses on silicosis and countermeasures. Priority should be given to training trainers.

Recommendations regarding systematic foundry reports:

Collection of foundry information using Form 3 should continue so that data can be updated.

The Presidium of the VGCL invests trade unions in cities, provinces, and industries where there are foundries with the responsibility for collecting Form 3 data and sending to the NILP. This should be done annually, with reports being sent by the end of November.

The NILP needs financial support from the VGCL, with a total of about 20 million VND for remuneration of those who fill in Form 3 and send to the NILP and for the assessment of data.

The collected data then will be disseminated to all members of the national taskforces on the elimination of silicosis.

Updated by PAP/SUT/TRS. Approved by BKL. Last updated on 16 November 2000