Regulations on white asbestos dust concentration in Vietnam are at strict levels.

Fibro cement roofing panels at Montreux station in Switzerland in 2019.

How is the world using white asbestos?

Asbestos is the trade name used to refer to a variety of mineral fibers mined from natural rock layers and they are divided into many different colors such as white, brown and blue asbestos.

Among them, brown and blue asbestos, with rough, needle-like structures, when entering the lungs will cause mesothelioma lesions, have been banned worldwide. Only white asbestos is the only fiber still used for commercial purposes in many large countries such as Russia, the US, China, India, ASEAN countries... The annual output of white asbestos mining is up to 2 million tons with the main producers being Russia, China, Brazil, Kazakhstan, and India. China is currently the world's largest consumer with more than 500,000 tons/year to serve its developing industries.

Nowadays, to meet the requirements of public health safety, only products containing high levels of white asbestos are allowed to be produced and used because the white asbestos fibers are tightly bonded in the cement structure, reducing the risk of releasing fibers into the environment. Common materials using asbestos-cement mixtures include fiber cement roofing sheets, tiles, wall panels, water pipes, water tanks, etc.

Vietnam's regulations regarding white asbestos are more stringent than many other countries.

Each country sets regulations to control the concentration of fiber dust in the air and ensure a safe working environment, protecting the health of workers and people exposed to asbestos.

In the US, the maximum allowable concentration is 0.1 fiber/ml in a work shift, India allows 1.0 fiber/ml, in Russia it is 2.0 fiber/ml. Regulations in other ASEAN countries such as the Philippines are 2.0 fiber/ml; Indonesia is 1.0 fiber/ml; Thailand is 5.0 fiber/ml.

Similar to other countries, Vietnam regulates the concentration of white asbestos dust in the air at the workplace equivalent to the US standard of 0.1 fiber/ml of air averaged over 8 hours and not exceeding 0.5 fiber/ml of air averaged over 1 hour. This is a stricter level than many countries in the region and around the world.

In addition, enterprises in Vietnam must also conduct occupational health examinations for workers annually and organize monitoring and supervision of water and air environments in production facilities at a frequency of once every 3 months.

Fibro cement roofing sheets for houses of people in the highlands.

Is there a safety threshold and the possibility of controlled use of white asbestos?

White asbestos is composed of many small, porous and flexible fibers linked in a spiral shape to form a hollow, bendable cylindrical tube. This type of fiber is considered an ideal input material in the production of thousands of products applied in the fields of: construction materials, friction products such as brake pads, gaskets, fabrics, heat-resistant clothing, aviation industry, pharmaceutical industry, military, space... Many industrialized countries in the world today still use white asbestos because they cannot find any alternative material that is more effective and superior.

Most of the white asbestos is imported into Vietnam to produce fiber cement roofing sheets, a type of sheet favored by the poor because it is cheap, durable, and can withstand alkaline environments and harsh climates of mountainous provinces and coastal areas.

However, this material has also caused much controversy over the past 20 years about its potential impact on human health, although domestic scientific research has confirmed that no cases of cancer due to exposure to white asbestos have been found.

According to the research of the Institute of Construction Materials - Ministry of Construction in 2014 on the dust-generating ability of roofing sheets, white asbestos fibers are deeply bonded to hydrated cement stone. The hydrated minerals of the cement cover and penetrate deeply into the pores of the white asbestos fibers, creating a durable structure that is difficult to spread out, so it almost does not cause risks to the environment and human health. In particular, when the fiber cement sheet is washed away, its residue is no longer pure white asbestos fibers but cement stone containing a small part of the fibers that are very tightly bonded, unable to float in the air and be inhaled into the lungs.

Dr. Le Thi Hang - Former Director of Construction Hospital - Ministry of Construction said that for many years, the Hospital has been monitoring and supervising the health status of workers in the fiber cement roofing sheet manufacturing industry and occupational cancer due to exposure to white asbestos. Research results show that the level of occupational disease hazard in the fiber cement roofing sheet manufacturing industry in Vietnam is very low. No cases of workers with asbestosis and malignant lesions related to asbestos such as lung cancer and mesothelioma have been detected. The concentration of fiber dust in the working environment at the factories meets the permitted standards.

For users of fiber cement roofing sheets, the study investigated the health status and mortality rate of people in Tan Trinh commune, Quang Binh district, Ha Giang province - where 69.4% of households use AC roofing sheets for roofing. Environmental surveys at 30 locations in Tan Trinh commune showed that no asbestos fibers were detected in the measured samples. The crude mortality rate in Quang Binh, Ha Giang is at an average level compared to other regions in Vietnam and the world.

In 2015, the Asian Industrial Health Association conducted an investigation to assess air quality by measuring the amount of white asbestos fibers in the environment when replacing, installing and adding new fibro-cement roofing sheets at the following locations: Ninh Hiep Cultural House, Ninh Hiep; Thanh Cong Textile Export Company Limited - Bo Xuyen Ward - Thai Binh; Dong Nhue Village Community House, My Thinh Commune, Nam Dinh City; Ma Van Lai Construction Materials Store, Nga Son, Thanh Hoa and Km 26 Dong Anh Materials Construction Investment Joint Stock Company, Dong Anh District.

Image of workers replacing old fiber cement roofing sheets with new roofing sheets

The results showed that the amount of fiber dust measured on the body of workers at the construction site when dismantling old fibro-cement roofing sheets and installing new fibro-cement roofing sheets using hand drills were all below the prescribed threshold.

Scientists and experts who have worked and studied in the field of silicosis believe that, in principle, all substances have the potential to cause disease, however, they depend on three factors: size, exposure dose and duration of stay in the body. Whether an object or substance is considered safe or a disease-causing risk depends largely on how we humans use them every day. White asbestos can be used completely safely. The same goes for white asbestos, the problem is controlled use./.