Question # 508

508. Hydrochloric acid, also known as hydrogen chloride (CAS number 7647-01-0), is a toxic chemical under EPCRA section 313. Hydrochloric acid can exist in both aqueous solution and in a gaseous, anhydrous form. On July 25, 1996, EPA modified the listing of hydrochloric acid to include only acid aerosols including mists, vapors, gas, fog and other airborne forms of any particle size (61 FR 38600). Does the modified listing of hydrochloric acid refer to both the aqueous and the anhydrous forms of this chemical?
Yes. The CAS number 7647-01-0 identifies both aqueous and anhydrous forms of hydrochloric acid. The listing modification also applies to both aqueous and anhydrous forms of hydrochloric acid.