NIOSHTIC-2 Publications Search
Intended use and application of the TLV's.
Transactions of the 33rd Annual Meeting of the American Conference of Governmental Industrial Hygienists, May 24-28, 1971, Toronto, Ontario, Canada. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, 1971 May; :113-116
A discussion is presented on the importance of the documentation behind the establishment of threshold limit values (TLV) in the determination of the usefulness of TLV's as toxic agent standards. The bases for the establishment of TLV's for the industrial organic isocyanate-TDI (1321386), phosgene (75445), trichloroethylene (79016), sulfur-dioxide (7446095), and mineral oil mists are presented and compared, to demonstrate the importance of documentation in interpreting the meaning of the TLV. The TLV established for TDI (2 ppm) is a ceiling value which was selected to prevent irreversible pulmonary sensitization and to minimize recurrent allergic attacks, and therefore should never be exceeded, whereas, the TLV established for mineral oil mists (5 mg/cubic meter) is only a good housekeeping practice, and was not established for the prevention of injury. Occasional brief exposures to mineral oil mists exceeding the TLV are inconsequential. Understanding the basis behind the establishment of the TLV allows the hygienist to properly evaluate whether hazardous conditions exist during the use of potentially toxic substances, the seriousness of exposures, and whether or not the amount by which the estimated exposure exceeds the TLV is of sufficient magnitude to be of concern to the worker. Several examples of misuse of TLV values, by not considering their basis, are described.
Hygiene; Legislation; Toxins; Chlorinated-ethylenes
1321-38-6; 75-44-5; 79-01-6; 7446-09-5
Transactions of the 33rd Annual Meeting of the American Conference of Governmental Industrial Hygienists, May 24-28, 1971, Toronto, Ontario, Canada
Page last reviewed: May 5, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division