Must a stationary source owner or operator consider the amount of ammonia present in ammonium hydroxide that is contained in a process when determining whether the threshold for ammonia is exceeded?
The list of regulated toxic substances at 40 CFR Section 68.130 includes BOTH
“ammonia (anhydrous)” and
“ammonia (conc 20% or greater)”
but does not include a specific listing for “ammonium hydroxide.” The Chemical Abstract Registry Service (CAS) number for ammonium hydroxide is 1336-21-6, and the CAS number for ammonia is 7664-41-7. Ammonium hydroxide is, however, simply a mixture of ammonia and water.