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Appendix F: Miscellaneous Notes


The final OSHA Benzene standard in 1910.1028 applies to all occupational exposures to benzene except some subsegments of industry where exposures are consistently under the action level (i.e., distribution and sales of fuels, sealed containers and pipelines, coke production, oil and gas drilling and production, natural gas processing, and the percentage exclusion for liquid mixtures); for the excepted subsegments, the benzene limits in Table Z-2 apply (i.e., an 8-hour TWA of 10 ppm, an acceptable ceiling of 25 ppm, and 50 ppm for a maximum duration of 10 minutes as an acceptable maximum peak above the acceptable ceiling).

  • Octachloronaphthalene
  • Pentachloronaphthalene
  • Tetrachloronaphthalene
  • Trichloronaphthalene

IDLH values for these four chloronaphthalene compounds are unknown.  The Documentation for Immediately Dangerous to Life or Health Concentrations identified “Effective” IDLH values, based on analogy with other chloronaphthalenes and the then-effective NIOSH Respirator Decision Logic (DHHS [NIOSH] Publication No. 87-108; ).  These values for respirator recommendations were determined by multiplying the NIOSH REL or OSHA PEL by an assigned protection factor of 10.  This assigned protection factor was used during the Standards Completion Program for deciding when the “most protective” respirators should be used for these four chemicals.  Listed below are the “Effective” IDLH values that were determined using 10 times the REL or PEL for each chemical.  For more information please consult the IDLH Documentation.

“Effective” IDLH values that were determined using 10 times the REL or PEL for each chemical.
Chemical NIOSH REL/OSHA PEL “Effective” IDLH (10 X REL/PEL)

TWA 0.1 mg/m 3 *

1 mg/m 3

TWA 0.5 mg/m 3

5 mg/m 3

TWA 5 mg/m 3

50 mg/m 3

TWA 2 mg/m 3

20 mg/m 3

* NIOSH also recommends a STEL of 0.3 mg/m 3 for octachloronaphthalene; the TWA of 0.1 mg/m 3 was used to calculate the “Effective” IDLH of 1 mg/m 3 .

Page last reviewed: October 18, 2018