On February 3, 2020, the U.S. Chemical Safety and Hazard Investigation Board (CSB) released a prepublication version of a final rule establishing new requirements for owners and operators of stationary sources to report accidental releases of regulated substances or other “extremely hazardous substance[s]” into the ambient air within eight hours of such release. CSB was ordered to issue this rule last year in Air Alliance of Houston, et al. v. U.S. Chemical Safety and Hazard Investigation Board, 365 F. Supp. 3d 118 (D.D.C. Feb. 4, 2019). The new release reporting requirements are in addition to and do not replace those that already existed and are enforced by other agencies. However, if a release is reported to the National Response Center (NRC), the CSB reporting requirement may be satisfied by providing the NRC identification number to CSB within 30 minutes of submitting a report to the NRC. The rule describes when a report is required and specifies the content for such a report, which can be submitted either by telephone or by emailed form. Except in cases where there is a knowing failure to report, there will be a one-year delay in enforcing the final rule, as CSB will concentrate on compliance education during the first year the rule is effective.