APPENDIX G: Substances Whose Adopted Documentation and TLVs® Were Withdrawn For a Variety of Reasons, IncludingInsufficient Data, Regrouping, Etc

[Individual entries will remain for a 10-year period, commencing with the year of withdrawal]

Substance [CRN], Year Withdrawn, Reason
Acetylene [74-86-2] 2015 See Appendix F: Minimal Oxygen Content
Aliphatic hydrocarbon gases,  Alkanes [C1–C4] 2013 Methane, Ethane, Propane, Liquefied petroleum gas (LPG) and Natural gas — see Appendix F: Minimal Oxygen Content. Butane and Isobutane — see Butane, all isomers
Argon [7440-37-1] 2014 See Appendix F: Minimal Oxygen Content
n-Butyl acetate [123-86-4] 2016 See Butyl acetates, all isomers
sec-Butyl acetate [105-46-4] 2016 See Butyl acetates, all isomers
tert-Butyl acetate [540-88-5] 2016 See Butyl acetates, all isomers
Calcium chromate [13765-19-0], as Cr 2018 See Chromium and inorganic compounds
Calcium silicate, synthetic nonfibrous [1344-95-2] 2016 Insufficient data Chromite ore processing (Chromate), as Cr 2018 See Chromium and inorganic compounds
Chromyl chloride [14977-61-8] 2018 See Chromium and inorganic compounds
Cyclopentadiene [542-92-7] 2019 See Dicyclopentadiene, including Cyclopentadiene
Ethyl cyanoacrylate [7085-85-0] 2018 See Cyanoacrylates, Ethyl and Methyl
Glycerin mist [56-81-5] 2013 Insufficient data relevant to human occupational exposure

Helium [7440-59-7] 2014 See Appendix F: Minimal Oxygen Content
Hydrogen [1333-74-0] 2014 See Appendix F: Minimal Oxygen Content
Isobutyl acetate [110-19-0] 2016 See Butyl acetates, all isomers
Isopropyl acetate [108-21-4] 2018 See Propyl acetate isomers
Methyl 2-cyanoacrylate [137-05-3] 2018 See Cyanoacrylates, Ethyl and Methyl
Neon [7440-01-9] 2014 See Appendix F: Minimal Oxygen Content
Nitrogen [7727-37-9] 2014 See Appendix F: Minimal Oxygen Content
Nonane [111-84-2], all isomers 2012 See Nonane Oil mist, mineral 2010 See Mineral oil, excluding metal working fluids
Piperazine dihydrochloride [142-64-3] 2012 See Piperazine and salts
n-Propyl acetate [109-60-4] 2018 See Propyl acetate isomers Soapstone 2011 See Talc
Strontium chromate [7789-06-2], as Cr 2018 See Chromium and inorganic compounds

Tantalum [7440-25-7] and Tantalum oxide [1314-61-0] dusts, as Ta 2010 Insufficient data
Zinc chromates [11103-86-9; 13530-65-9; 37300-23-5], as Cr 2018 See Chromium and inorganic compounds