OSHA comments from the January 19, 1989 Final Rule on Air Contaminants Project extracted from 54FR2332 et. seq. This rule was remanded by the U.S. Circuit Court of Appeals and the limits are not currently in force.
CAS: 108-46-3; Chemical Formula: C6H4(OH)2
H.S. No. 1346
OSHA formerly had no limit for resorcinol. The proposed limit was an 8-hour TWA of 10 ppm and a 15-minute STEL of 20 ppm; the final rule establishes these limits. NIOSH (Ex. 8-47, Table N1) supports the selection of these PELs. The ACGIH has an 8-hour TWA limit of 10 ppm and a TLV-STEL of 20 ppm. Resorcinol occurs in the form of sweet-tasting white crystals that may turn pink on exposure to air and light or on contact with iron.
Resorcinol has been reported to be less toxic by ingestion or skin penetration than either catechol or phenol (von Oettingen 1949 and Koppers Company 1974, both as cited in ACGIH 1986/Ex. 1-3, p. 511). The oral LD(50) in rats is 301 mg/kg (NIOSH 1977i/Ex. 1-1182). Daily six-hour exposures at 8 ppm for two weeks produced no ill effects in rats, guinea pigs, and rabbits. Acute inhalation exposures to a resorcinol-water aerosol at concentrations as high as 7800 mg/m3 for one hour and 2800 mg/m3 for eight hours caused no toxic effects in laboratory animals (Koppers Company 1974, as cited in ACGIH 1986/Ex. 1-3, p. 511).
In humans, the cutaneous application of solutions or salves containing from 3 to 25 percent of this compound may result in local hyperemia, itching, dermatitis, edema, corrosion, and the loss of the superficial layers of the skin. If these damages are severe, they may be associated with some or all of the following effects: enlargement of regional lymph glands, restlessness, methemoglobinemia, cyanosis, convulsions, tachycardia, dyspnea, and death (Patty’s Industrial Hygiene and Toxicology, Vol. 2A, p. 2588, Clayton and Clayton, 1981). An epidemiologic study of rubber workers exposed to a hexamethylene-tetramine-resorcinol rubber system revealed no specific symptoms caused by resorcinol; the concentrations in air were less than 0.3 mg/m3. In another study, there were no reports of irritation or discomfort by workers when concentrations were 10 ppm or less for periods of at least 30 minutes (Patty’s Industrial Hygiene and Toxicology, Vol. 2A, p. 2588, Clayton and Clayton, 1981). Dr. Grace Ziem (Ex. 46) notes that resorcinol exposure is also associated with renal and hepatic effects and with methemoglobinemia.
In the final rule, OSHA is establishing a PEL of 10 ppm TWA and a STEL of 20 ppm for resorcinol. The Agency concludes that this combined limit will protect workers against the significant risks of irritation, methemoglobinemia, and other adverse effects, all material impairments of health that are associated with exposure to this substance at levels above the new PELs.