Ammonia (CAS# 7664-41-7) is an Extremely Hazardous Substance (EHS), listed at 40 CFR Part 355 Appendix A EPA website and Appendix B with a reportable quantity (RQ) of 100 lbs. Both ammonia and ammonium hydroxide (CAS# 1336-21-6) are listed as Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) hazardous substances at 40 CFR 302.4. Under CERCLA, ammonia is listed with an RQ of 100 lbs, and ammonium hydroxide is listed with an RQ of 1,000 lbs. A facility has a large storage tank of ammonium hydroxide solution. How does the facility report a release from this storage tank under the Emergency Planning and Community Right-to-Know Act (EPCRA) section 304 and CERCLA section 103? Does the CERCLA mixture rule apply to the release of ammonium hydroxide solution?