(a) Specialized definitions. (1) Benzidine Manufacturer means a manufacturer who produces benzidine or who produces benzidine as an intermediate product in the manufacture of dyes commonly used for textile, leather and paper dyeing.

(2) Benzidine-Based Dye Applicator means an owner or operator who uses benzidine-based dyes in the dyeing of textiles, leather or paper.

(3) The ambient water criterion for benzidine in navigable waters is 0.1 µg/l.

(b) Benzidine manufacturer—(1) Applicability. (i) These standards apply to:

(A) All discharges into the navigable waters of process wastes, and

(B) All discharges into the navigable waters of wastes containing benzidine from the manufacturing areas, loading and unloading areas, storage areas, and other areas subject to direct contamination by benzidine or benzidine-containing product as a result of the manufacturing process, including but not limited to:

(1) Stormwater and other runoff except as hereinafter provided in paragraph (b)(1)(ii) of this section, and

(2) Water used for routine cleanup or cleanup of spills.

(ii) These standards do not apply to stormwater runoff or other discharges from areas subject to contamination solely by fallout from air emissions of benzidine; or to stormwater runoff that exceeds that from the ten year 24-hour rainfall event.

(2) Analytical method acceptable—Environmental Protection Agency method specified in 40 CFR part 136.

(3) Effluent standards—(i) Existing sources. Discharges from a benzidine manufacturer shall not contain benzidine concentrations exceeding an average per working day of 10 µg/l calculated over any calendar month, and shall not exceed a monthly average daily loading of 0.130 kg/kkg of benzidine produced, and shall not exceed 50 µg/l in a sample(s) representing any working day.

(ii) New sources. Discharges from a benzidine manufacturer shall not contain benzidine concentrations exceeding an average per working day of 10 µg/l calculated over any calendar month, and shall not exceed a monthly average daily loading of 0.130 kg/kkg of benzidine produced, and shall not exceed 50 µg/l in a sample(s) representing any working day.

(4) The standards set forth in this paragraph (b) shall apply to the total combined weight or concentration of benzidine, excluding any associated element or compound.

(c) Benzidine-based dye applicators—(1) Applicability. (i) These standards apply to:

(A) All discharges into the navigable waters of process wastes, and

(B) All discharges into the navigable waters of wastes containing benzidine from the manufacturing areas, loading and unloading areas, storage areas, and other areas subject to direct contamination by benzidine or benzidine-containing product as a result of the manufacturing process, including but not limited to:

(1) Stormwater and other runoff except as hereinafter provided in paragraph (c)(1)(ii) of this section, and

(2) Water used for routine cleanup or cleanup of spills.

(ii) These standards do not apply to stormwater runoff or other discharges from areas subject to contamination solely by fallout from air emissions of benzidine; or to stormwater that exceeds that from the ten year 24-hour rainfall event.

(2) Analytical method acceptable. (i) Environmental Protection Agency method specified in 40 CFR part 136; or

(ii) Mass balance monitoring approach which requires the calculation of the benzidine concentration by dividing the total benzidine contained in dyes used during a working day (as certified in writing by the manufacturer) by the total quantity of water discharged during the working day.

(3) Effluent standards—(i) Existing sources. Discharges from benzidine-based dye applicators shall not contain benzidine concentrations exceeding an average per working day of 10 µg/l calculated over any calendar month; and shall not exceed 25 µg/l in a sample(s) or calculation(s) representing any working day.

(ii) New sources. Discharges from benzidine-based dye applicators shall not contain benzidine concentrations exceeding an average per working day of 10 µg/l calculated over any calendar month; and shall not exceed 25 µg/l in a sample(s) or calculation(s) representing any working day.

(4) The standards set forth in this paragraph (c) shall apply to the total combined concentrations of benzidine, excluding any associated element or compound.