2-Methoxypropan-1-ol. Documentation of proposed values of occupational exposure limits (OELs)

2-Methoxypropan-1-ol is a by-product of a propylene glycol methyl ether (PGME) manufacturing process, in which it is an impurity at concentrations up to 5%. 2-Methoxypropan-1-ol as a PGME impurity can occur in industry in paints solvents, varnishes, dyes, inks, adhesion agents, ingredients in cleaning formulations and chemical synthesis intermediates. It may also occur as an impurity in cosmetics, although its use in these products is prohibited. At occupational exposure, 2-methoxypropan-1-ol may be absorbed through inhalation and skin. There are no data on the number of people exposed to this compound in Poland and no data on its toxic effects in humans. There is only one study that showed a statistically significant increase in the occurrence of birth defects in children of mothers exposed to 2-methoxypropan-1-ol. The proposed MAC value for 2-methoxypropan-1-ol (20 mg/m3) is based on the systemic toxicity demonstrated in a study on pregnant rabbits (NOAEC value of 1335 mg/m3). Due to its irritant effects, STEL value of 40 mg/m3 and “I” notation are also proposed. There is no basis for establishing a BEI value. Since dermal exposure may contribute significantly to the absorption of 2-methoxypropan-1-ol by workers, a "skin" notation is also required.

Governing Occupational Exposure Using Thresholds: A Policy Biased Toward Industry

Strongly grounded in scientific knowledge, the instrument known as occupational exposure limits or threshold limit values has changed government modalities of exposure to hazardous chemicals in workplaces, transforming both the substance of the problem at hand and the power dynamics between the actors involved. Some of the characteristics of this instrument favor the interests of industries at the expense of employees, their representatives, and the authorities in charge of regulating these risks. First, this instrument can be analyzed as a boundary object that has very different uses in space and time. In particular, it is increasingly masking its industrial origins to appear as an instrument that is almost exclusively based on scientific rationale. In the case of asbestos and its substitutes, the use of an instrument relying on scientific expertise generates a specific temporality of implementation that allows manufacturers to take advantage of periods during which regulations are either nonexistent or very loose. Finally, the choice of a technoscientific definition of the issues contributes to shifting the negotiations to a field where companies are in a position of strength and their opponents are weakened.

The Scientific Basis for Occupational Exposure Limits for Hydrogen Sulphide—A Critical Commentary

Objectives: Occupational exposure limits for hydrogen sulphide (H2S) vary considerably; three expert group reports, published from 2006 to 2010, each recommend different limits. Some jurisdictions are considering substantial reductions. Methods: This review assesses the scientific evidence used in these recommendations and presents a new systematic review of human studies from 2006–20, identifying 33 studies. Results: The three major reports all give most weight to two sets of studies: of physiological effects in human volunteers, and of effects in the nasal passages of rats and mice. The human studies were done in one laboratory over 20 years ago and give inconsistent results. The breathing style and nasal anatomy of rats and mice would make them more sensitive than humans to inhaled agents. Each expert group applied different uncertainly factors. From these reports and the further literature review, no clear evidence of detrimental health effects from chronic occupational exposures specific to H2S was found. Detailed studies of individuals in communities with natural sources in New Zealand have shown no detrimental effects. Studies in Iceland and Italy show some associations; these and various other small studies need verification. Conclusions: The scientific justification for lowering occupational exposure limits is very limited. There is no clear evidence, based on currently available studies, that lower limits will protect the health of workers further than will the current exposure limits used in most countries. Further review and assessment of relevant evidence is justified before exposure limits are set.