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New chemicals, old risks: why careful monitoring must be maintained

Potentially harmful chemicals permeate today's workplaces. While the number of chemicals used in industry now exceeds 50,000, an additional 500 new chemicals are introduced in industry every year. The toll from chemical exposure is heavy - the ILO estimates that of the 2 million work-related fatalities, 439,000 are caused by chemicals, and of the 160 million cases of work-related disease, 35 million are due to chemicals. A new ILO publication says the toxicity of new chemicals must be checked for safety and health more carefully before marketing. The 17th World Congress on Safety and Health at Work will address safety and health of chemicals during a special session on 19 September 2005.

Article | 26 August 2005

GENEVA - In a Korean electronics factory where 2-bromopropane was used as an alternative solvent, early on-set menopause was found in 16 exposed female workers in 1995. Additionally, the chemical produced serious negative effects on the male reproduction system. After about two years, ovary function had recovered in only two female workers, one of whom gave birth to a child while the other recovered menstruation.

Many animal experiments have confirmed the severe reproductive toxicity of 2-bromopropane in both female and male animals. In place of 2-bromopropane, 1-bromopropane started to be used in industry although not enough information was available on its toxicity. In animal experiments a severe neurotoxicity of 1-bromopropane to both the central nervous system and the peripheral nerves was found.

In Japan, manufacturers and suppliers of 1-bromopropane proceeded with care. "Fortunately, no reports of serious poisoning involving 1-bromopropane have surfaced in Japan. However, the first serious case of 1-bromopropane poisoning was reported in the United States in 1999", explains Yasuhiro Takeuchi, Emeritus Professor of Nagoya University in a new ILO publication.

"In his work, a 19-year-old male patient used 1-bromopropane to clean metal parts. He noticed paresthesia in January 1998. The symptoms gradually worsened, with weakness occurring in proximal portions of both lower extremities and the right hand. He was admitted to the hospital about two months after he had started using 1-bromopropane on the job".

At admission, he could not stand up by himself, and both swallowing and urination were difficult.

On the basis of the clinical findings and MRI examination, he was diagnosed as having encephalomyeloradiculopathy causing disorders of the central nervous system.

Since that case, at least three other severe cases of 1-bromopropane poisoning have occurred in the United States. Neurological impairment was also found among the workers exposed to 1-bromopropane in a factory in China which produced about 6,000 tons of 1-bromopropane, and exported 1-bromopropane to the United States, Germany, France and other countries in 2003.

On October 5, 2004, at the annual meeting of the American Neurological Association held in Salt Lake City, Utah, Dr. J.J. Majersik and colleagues reported six cases of poisoning with 1-bromopropane. They were exposed to 1-bromopropane while using spray adhesives to glue foam cushions. All of the patients complained of lower extremity pain or paresthesia, and five out of the six patients reported difficulty in walking. Eighteen months later, the two most severely affected patients had regained minimal function but still required assistance to walk. Three patients continued to experience chronic neuropathic pain. One patient had subtle cognitive changes.

According to Takeuchi, "1-bromopropane is a rare chemical in that animal experiments predicted the potential risk of it. Generally speaking, when new chemicals are introduced in industry, it is impossible to know where, by whom and for what purpose they will be used; poisoning may thus occur at workplaces where it is not expected".

Substantial amounts of chemicals are produced in large companies and supplied to all sorts of workplaces, including small workplaces where the workers are not well protected. Industry has a need for ever more sophisticated skills and new materials in order to be competitive. Thus many new chemicals are introduced in the production of new, competitive goods such as medicines, dyestuffs, agricultural chemicals, clothes and others.

In Japan from 1979 to 2003, the cumulative number of new chemicals reached more than 12,000. By law, the mutagenicity of new chemicals must be tested, to screen for carcinogenicity and reproductive toxicity, before they can be marketed in Japan. About 4 per cent of the new chemicals are strongly mutagenic and 9 per cent are weakly mutagenic.

However, in addition to mutagenicity, chemicals have various other toxicities, and may cause health disorders. Specific fluorochlorocarbons and 1,1,1-trichloroethane were prohibited in 1996 because of their ozone-layer depleting potentials.

"Industrial chemicals are not tested for safety and health as stringently as medicines and foods, because they are not produced for human intake. The toxicity of new chemicals should be checked for safety and health before marketing. New chemicals should be taken into use with care in order to prevent them from poisoning workers", concludes Takeuchi.

The ILO and safe use of chemicals at work

ILO action in the field of chemicals at work includes the creation of alliances and partnerships to promote safe use of chemicals at work, direct technical assistance and the promotion of standards and guidelines for governments, the social partners and other groups.

ILO has joined forces with other organizations in providing technical advice to member States. For example, with the United Nations Institute of Training and Research (UNITAR), the ILO initiated the UNITAR/ILO Globally Harmonized System of Classification and Labelling of Chemicals (GHS) Capacity Building Programme in 2001. To date, pilot activities have been conducted in South Africa and Zambia and regional activities in Southern Africa and South America. In 2005-6, UNITAR/ILO will be supporting national GHS capacity building projects in Indonesia, Nigeria, Senegal, Slovenia, Thailand, the Gambia and the Philippines.

The International Programme on Chemical Safety (IPCS), a collaborative effort between the ILO, WHO and UNEP, produce the International Chemical Safety Cards. To date, nearly 1400 hundred cards have been developed and have been translated into some 20 languages and disseminated.

Major hazard control projects have been arranged in India and Indonesia, and the African and Asian-Pacific regional programmes have arranged a number of workshops, expert visits, and disseminated information in the regions.

More than 70 ILO Conventions and Recommendations relate to questions of safety and health. In addition, the ILO has issued more than 30 Codes of Practice on Occupational Health and Safety, including the ILO Code of Practice on Safety in the Use of Chemicals at Work 1993.

The Chemicals Convention, 1990 (No. 170) and its accompanying Recommendation (No. 177) represent international efforts to upgrade the national measures and harmonize regulatory standards. They emphasize the need to establish a coherent national policy of chemical safety ranging from the classification and labelling of chemicals to the control in all aspects of the use of chemicals. Particular emphasis would thus be placed on roles and responsibility of the competent authority, suppliers and employers, as well as duties and rights of workers.

The Prevention of Major Industrial Accidents Convention, 1993 (No. 174) and its accompanying Recommendation 1993 (No. 181) aims to protect workers, the public and the environment from major industrial accidents, in particular through the prevention of major accidents involving hazardous substances and the limitation of the consequences of such accidents. It applies to major hazard installations with the exception of nuclear installations and radioactive materials processing, military installations and transport outside the site of an installation other than pipeline.

The Asbestos Convention, 1986 (No. 162) and its accompanying Recommendation (No.172) advances organizational, technical and medical measures to protect workers against hazardous asbestos dust. Other ILO Conventions and Recommendations refer to anthrax prevention, the use of white lead and benzene, radiation protection and occupational cancer.

Note 1 - Asian-Pacific Newsletter on Occupational Health and Safety 2005; N° 12: 10-11.