The air emission standards (Subpart CC of 264 and 265) require owners and operators to control organic air emissions from tanks managing hazardous wastes with an average volatile organic (VO) concentration greater than or equal to five hundred ppm by weight (§§264.1082(c)(1) and 265.1083(c)(1)). Air emission controls for tanks are divided into two levels based on temperature of vapor pressure determination, maximum organic vapor pressure of the waste, and whether the tank is used in a waste stabilization process. The owner or operator of the tank is responsible for determining whether Tank Level 1 or Tank Level 2 controls are applicable (§§264.1084(b) and 265.1085(b)).
Owners or operators of tanks subject to Level 1 controls are required to install a tight-fitting cover (i.e., fixed roof) and must determine the maximum organic vapor pressure for each hazardous waste placed in the tank (§§264.1084(c) and 265.1085(c)).
Owners or operators of tanks subject to Level 2 controls may use the following options to meet air emission standards: external floating roof, fixed roof with internal floating roof, vent to control device, pressure tank, or vent to an enclosed combustion device (§§264.1084(d) and 265.1085(d)).
Additional guidance on the air emission standards for tanks is available in the following documents:
RCRA Organic Air Emission Standards for TSDFs and Generators (EPA530-F-98-011); July 1, 1998 (RCRA Online 50603) [PDF 332K] or Order Online
Memo, Taunton to Barth; March 27, 1997 (RCRA Online 14288)
Monthly Call Center Report Question; February 1996 (RCRA Online 13777)