Updating of hygiene standards for carbon disulfide based on health risk assessment.

In 1995 the hygiene occupational standard values of carbon disulfide (CS2) were established in Poland: the maximum allowable concentration, eight-hour time weighted average (MAC-TWA)--18 mg/m3, and the short time exposure level (STEL)--30 mg/m3. For lack of reliable retrospective data on the CS2 exposure levels in the work environment and the dose-response relationship, the following have been taken into account in establishing these values: the nervous and vascular systems are recognized as the main CS2 exposure targets; long-term exposure to CS2 in the work environment, exceeding 30 mg/m3, induces the toxic effect in the nervous and cardiovascular systems; chronic exposure to CS2 at concentration below 20 mg/m3 does not produce adverse effects in the peripheral nervous and vascular systems; coronary heart disease does not occur more frequently in workers exposed to CS2. Aiming at updating the 1995 MAC value for CS2 the authors carried out an analysis of the recent literature data on the relation between exposure levels and health risk. The results of clinical and epidemiological studies published in 1995-1997 did not provide evidence that adverse health effects in the cardiovascular and neurological systems in persons occupationally exposed to CS2 at concentration below 48 mg/m3 is likely to occur. The studies of the harmful effects of low CS2 concentration on the reproductive system have not proved that CS2 affects the embryo and fetus. Moreover, in Poland the employment of women under conditions of CS2 exposure (regardless of concentrations) during pregnancy and breast feeding is banned. Because the latest reliable studies have not indicated that chronic CS2 exposure at the level of 20-48 mg/m3 exerts toxic effect on humans, CS2 concentration of 18 mg/m3 as MAC-TWA and 30 mg/m3 as STEL, adopted in 1995, need not to be updated.