The U.S. Environmental Protection Agency (EPA) has issued updated regulations for volatile organic liquid (VOL) storage vessels under the New Source Performance Standards (NSPS) program. The new rule—codified at 40 CFR Part 60, Subpart Kc (NSPS Kc)—applies to VOL storage vessels that are constructed, modified, or reconstructed after October 4, 2023.

This Tora Brief highlights key provisions of NSPS Kc with a particular focus on asphalt storage tanks, and compares the updated requirements to those of the previous standard, NSPS Kb (40 CFR Part 60, Subpart Kb).

Notably, NSPS Kc—like its predecessor—does not apply to pressure vessels designed to operate above 29.7 psia and without emissions to the atmosphere. This exemption includes pentane bullet tanks, which typically operate around 250 psia and use a nitrogen blanket to prevent atmospheric emissions. Process tanks, such as coating surge tanks, also remain outside the scope of the rule.