May 10, 2012

New Guidance on P046 Phentermine Listing

Phentermine is an oral appetite suppressant that has been in use since Food and Drug Administration approval in 1959. When used in conjunction with diet and exercise, phentermine may help patients to lose weight.

Phentermine is listed in §261.33(e) as P046 under two names: 1) benzeneethanamine, alpha, alpha-dimethyl-; and 2) alpha, alpha-dimethylphenethylamine. While it’s clear the listing description for P046 will apply to pure, unused phentermine managed for disposal, what isn’t clear is whether salts of phentermine (e.g., phentermine HCl) fall under the listing description.

In a new guidance memo [RO 14831], EPA has clarified that phentermine salts are not included in the scope of the P046 hazardous waste listing. P046 applies only when unused phentermine base (CAS# 122-09-8) is discarded. This agency guidance is significant because the chemical that is in use in medical applications is often one of several phentermine salts.

EPA based their decision on an analysis of the regulatory language, background documents from the initial P- and U-listings rulemaking, and previous agency guidance. The substance name for P046 in the regulatory listing at §261.33(e) does not reference salts or other formulations of phentermine. In contrast, approximately 30 other P- and U-listed wastes specifically include salts in the listing description (e.g., nicotine and warfarin). Finally, EPA cited previous agency guidance stating that unless a listing description specifically refers to the salt(s) of a chemical listed in §261.33, the salt(s) are not considered to be included in the scope of the listing. [RO 11489, 12155, 14778]

The agency provided two caveats to this guidance. First, while unused phentermine salts are not P046 listed waste when discarded, an unused chemical or formulation containing a phentermine salt will be a RCRA hazardous waste if it exhibits a characteristic. Second, this clarification applies to the federal program—authorized states can regulate phentermine salts more stringently. Thus, generators should check with their state to confirm the correct interpretation for their location.


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