• Hazardous and Toxic Substances

• Occupational Health Guidelines to Chemical Hazards. DHHS (NIOSH) Publication No. 81-123 (1981, January), 13 pages. This site contains PDF files of chemical information, such as exposure limits, health hazards, chemical and physical properties, monitoring and measuring procedures, personal protective equipment, etc.
• Understanding Toxic Substances, An Introduction to Chemical Hazards in the Workplace. California Occupational Health Branch, 10 pages. Includes a discussion of exposure limits.
• AIHA's Position on Permissible Exposure Limits (PELs). American Industrial Hygiene Association (1998, January 2), 1 page.
• AIHA's White Paper on Permissible Exposure Limits (PELs). American Industrial Hygiene Association (1993, January 19), 5 pages. OSHA has not been able to set up-to-date PELs for every chemical of concern in the workplace, these comments suggest what employers and industrial hygienists may do to fill the need.
• Currently, approximately 500 PELs have been established. Existing PELs are contained in 29 CFR 1910.1000, the air contaminants standard. Most PELs are listed in TABLE Z-1. TABLE Z-2 contains PELs for the following substances:

• PELs for exposure to mineral dusts can be found in TABLE Z-3. Mineral dusts listed include silica (crystalline and amorphous), silicates, graphite, coal dusts and inert or nuisance dusts.
• The PELs for several chemicals and hazards are included in chemical specific standards. These are: 
  • 1910.1001, 1915.1001, 1926.1101, Asbestos
  • 1910.1002, Coal tar pitch volatiles; interpretation of term
  • 1910.1003, 13 Carcinogens (4-Nitrobiphenyl, etc.) includes:
    • 1910.1004, alpha-Naphthylamine
    • 1910.1006, Methyl chloromethyl ether
    • 1910.1007, 3,3'-Dichlorobenzidine (and its salts)
    • 1910.1008, bis-Chloromethyl ether
    • 1910.1009, beta-Naphthylamine
    • 1910.1010, Benzidine
    • 1910.1011, 4-Aminodiphenyl
    • 1910.1012, Ethyleneimine
    • 1910.1013, beta-Propiolactone
    • 1910.1014, 2-Acetylaminofluorene
    • 1910.1015, 4-Dimethylaminoazobenzene
    • 1910.1016, N-Nitrosodimethylamine
  • 1910.1017, Vinyl chloride
  • 1910.1018, Arsenic, Inorganic
  • 1910.1025, Lead
  • 1910.1027, 1926.1127, Cadmium
  • 1910.1028, Benzene
  • 1910.1029, Coke oven emissions
  • 1910.1043, Cotton dust
  • 1910.1044, 1,2-dibromo-3-chloropropane
  • 1910.1045, Acrylonitrile
  • 1910.1047, Ethylene oxide
  • 1910.1048, Formaldehyde
  • 1910.1050, Methylenedianiline
  • 1910.1051, 1,3-Butadiene
  • 1910.1052, Methylene Chloride

• Critical Issues in Developing Permissible Exposure Limits for Air Contaminants. Roger O. McClellan, Chemical Industry Institute of Toxicology (CIIT), (1996), 6.60 MB PDF, pages 8 - 10.
• See the Safety and Health Topics page for Sampling & Analysis.

• How an airborne hazard is best controlled depends on the nature of the hazard and the process and possibility that workers will be exposed. Whenever possible, airborne hazards should be engineered out of a process. If it is not possible to reduce the hazard, appropriate personal protective equipment must be used. If employers need assistance complying with PELs, several OSHA resources for assistance are available.
• The following Safety and Health Topics pages provide additional information on control strategies:
   
• Personal Protective Equipment
• Respiratory Protection
• Ventilation

The Compliance section is on a separate page.

• Standards Development. Explanation of the process by which OSHA develops and promulgates standards.
• ACGIH. Many standards are based on the threshold limit values (TLV) established by the American Conference of Governmental Industrial Hygienists (ACGIH). This group provides low cost publication of its TLVs, as well as many other useful materials.
• 1988 NIOSH PEL Project Documentation. Database derived from OSHA comments from the June 19, 1988 Final Rule on Air Contaminants Project extracted from 54FR2324 et. seq. The rule was remanded by the U.S. Circuit Court of Appeals and these limits are not currently in force.