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Key words: ethylene glycol monobutyl ether, isoprene, isopropyl acetate, Occupational exposure limit, propyleneimine ether
The Committee for Recommendation of Occupational Exposure Limits, Japan Society for Occupational Health
Occupational Exposure Limits (OELs) for Chemical Substances
Ethylene glycol monobutyl ether [CAS No. 111-76-2], or 2-butoxyethanol, is a colorless liquid at room temperature (boiling temperature 171.2°C; saturated vapor pressure 0.76 mmHg (20°C)) with a gentle odor and is used as a solvent for paints, print inks, dyes, detergents, brake fluids, pesticides, and plasticizers. The Japan Society of Occupational Health (JSOH) proposes 20 ppm (97 mg/m3) as OEL-Ceiling (OEL-C) for ethylene glycol monobutyl ether based on human experience that no strong irritative symptom was observed at 20 ppm for 2 hours1}, while the symptom appeared when exposed to 98-195 ppm2). Exposure to concentrations below 20 ppm is expected to pre- vent hemolytic anemia and to minimize reproductive toxicity. A skin absorption notation and reproductive toxicant classification of group 2 are proposed.
Isoprene [CAS No. 78-79-5] is an odiferous, colorless, volatile liquid (boiling temperature 34°C; saturated vapor pressure 53.2 kPa (20°C) used as a raw material for producing synthetic and natural rubber, polyisobutylene, and butyl rubber. It is inflammable and may form explosive peroxide if polymerized in the presence of heat or various chemicals. The JSOH proposes 3 ppm (8.4 mg/m3) as the OEL-Mean (OEL-M) for isoprane based on toxicity testing results. No-observed-adverse-effect-level (NOAEL) in mice was considered 10 ppm based on observed pathological changes : increase in spinal degeneration at or above 70 ppm within a recovery period in male after 26week inhalation (70-7000 ppm)3-5), increased incidence of Harderian gland adenoma at or above 70 ppm, and local metaplasia in airway and olfactory epithelium at or above 140 ppm (male) and...