The substance caprolactam (CAS number 105602) is deleted from the list of hazardous air pollutants established by 42 U.S.C. 7412(b)(1).

[61 FR 30823, June 18, 1996]

The substance methyl ethyl ketone (MEK, 2-Butanone) (CAS Number 78-93-3) is deleted from the list of hazardous air pollutants established by 42 U.S.C. 7412(b)(1).

[70 FR 75059, Dec. 19, 2005]

The following definition of the glycol ethers category of hazardous air pollutants applies instead of the definition set forth in 42 U.S.C. 7412(b)(1), footnote 2: Glycol ethers include mono- and di-ethers of ethylene glycol, diethylene glycol, and triethylene glycol R-(OCH2CH2)n-OR′.

Where: n = 1, 2, or 3; R = alkyl C7 or less; or R = phenyl or alkyl substituted phenyl; R′= H or alkyl C7 or less; or OR′ consisting of carboxylic acid ester, sulfate, phosphate, nitrate, or sulfonate. [65 FR 47348, Aug. 2, 2000]

The substance ethylene glycol monobutyl ether (EGBE,2-Butoxyethanol) (CAS Number 111-76-2) is deleted from the list of hazardous air pollutants established by 42 U.S.C. 7412(b)(1).

[69 FR 69325, Nov. 29, 2004]

(a) The substance 1-bromopropane, or 1-BP, also known as n-propyl bromide or nPB (CAS No. 106-94-5) is added to the list of hazardous air pollutants established by Clean Air Act (CAA) section 112(b)(1), 42 U.S.C. 7412(b)(1).

(b) [Reserved]

[87 FR 396, Jan. 5, 2022]