MODULE 7: PSYCHOSOCIAL ISSUES AND OTHER MISCELLANEOUS TOPICS IN OCCUPATIONAL AND ENVIRONMENTAL HEALTH SECTION 10: STANDARD SETTING IN OCCUPATIONAL AND ENVIRONMENTAL HEALTH: 4. The International Debates On Standard Setting

4. THE INTERNATIONAL DEBATES ON STANDARD SETTING:

Over the last two decades there has been considerable debate in the scientific literature about the origins of exposure limits, particularly the Threshold Limit Values of the American Conference of Governmental Industrial Hygienists (ACGIH). These debates have an international significance, because the TLV's have formed the basis of OELs in many countries throughout the world, including developed West European countries, the Scandinavian countries and Japan. This experience has been replicated in the developing countries, including South Africa.

The ACGIH had established a TLV Committee which issued annual reports since 1946. However at that time, and for years subsequently, data available to establish exposure limits was almost non-existent in the public domain. This meant that the process of standard setting had to be based on toxicological data the companies themselves were compiling. Although these TL:V's have been published since the mid forties, they were not regulatory or enforceable standards. In 1970, in an attempt to establish legal enforceable standards, the Occupational Safety and Health Administration (OSHA) in the US used the 1968 set of TLV's as its list published under the new Occupational Safety and Health Act. Thus, standards whose origins at that time were unclear, became the legal OEL (OSHA's Permissible Exposure Limits (PELs)) in the US.

Castleman and Ziem (1988) in their review of the TLV Committee documentation showed that several key industry based toxicologists were either members or had close collaboration with the TLV Committee. In many instances, toxicologists from companies manufacturing a particular product were almost exclusively responsible for the setting up of the TLV for that compound. This had some important implications. Unpublished company memos were key to the development of TLVs for at least 104 products, and for at least 15 TLV's were based solely on such documentation. Companies were obviously placing economic interests above those of health, and additionally, the adherence to this TLV could give rise to the "TLV defense" should companies be challenged in court.

The non-scientific basis of the TLV's is evident for several chemicals. The TLV for benzene (present on the original TLV list) was at 100 ppm in 1946, dropped to 50ppm two years later, 35 the following year and by 1990 to 0.1ppm with little indication that this was due to new scientific data becoming available at each time, except perhaps by 1990 (Rappaport, 1993).

The ACGIH’s TLVs have in the main continued to follow a downward trend. However, as true processes are not available for public scrutiny, to what extent rule revisions are due to corporate influence and to what extent they are driven by health based concerns are uncertain. For these reasons, their widespread exportation to other countries, and adoption as the standards in those countries must be viewed with caution. Attempts by OSHA (US) to reduce the levels of its 1970 standards in the mid eighties (revisions based on NIOSH’s Recommended Exposure Limits) was thrown out by the American courts following action instituted by the corporate sector.

INTERACTIVE EXERCISE:

You have been appointed Chief Director: Occupational Health and Safety in the Department of Labour. It has come to your notice that the Hazardous Chemical Substances Regulations does not provide an OEL for the chemical XYZ. Manufacture of this chemical has only recently been commenced in South Africa. Explain how you would go about establishing an occupational exposure limit for this substance.