Several extremely hazardous substances (EHSs) have two threshold planning quantities (TPQs) listed in 40 CFR 355 Appendix A. When is the higher TPQ used?

A facility would only apply the 10,000 pound TPQ for an EHS when complying with the emergency planning notification requirements of EPCRA Section 302 and 40 CFR 355. For the purposes of EPCRA Section 311 or 312 and 40 CFR 370 SDS and Tier II reporting, a facility would reference the lower TPQ in Part 355, Appendix A, and then only use either a threshold of 500 pounds or the referenced TPQ in Part 355, Appendix A, whichever is lower. For more information, see 40 CFR 355.15 and 40 CFR 370.10(a)(1).