Asbestos

Regulatory Standards History

Regulatory Standards

• 1948-1973: TLV-TWA, 5mppcf
• 1968-1969: TLV-TWA, 12 fiber/cm3
• 1970-1978: TLV-TWA, 5 fiber/cm3n
• 1978:
  • TLV-TWA, 2 fiber/cm3 (Chrysoltile and other)
  • TLV-TWA, 0.5 fiber/cm3 (Amosite and Treolite)
  • TLV-TWA, 0.2 fiber/cm3 (Crocidolite)
• 1991: TLV-TWA, 0.2 fiber/cm3 (all forms)
• 1997-current: TLV-TWA, 0.1 fiber/cm3\

Current Standards

1. TLV-TWA: 0.1 fiber/cm3 (fiber >5 _m).
   a. 8-hour workday, 40-hour workweek.
   b. Repeat, daily exposure without adverse effect
2. OSHA PEL-TWA: 0.1 fiber/cm3
   a. <0.5 fiber/cm3 (for 30 min sampling time)
3. 3) NIOSH REL-TWA: 0.1 fiber/cm3