Are DEA Registrants legally allowed to destroy unused controlled substances on site?

Yes. According to 21 CFR 1300.05, “A controlled substance is destroyed on-site when destruction occurs on the physical premises of the destroying registrant's registered location. A hospital/clinic has an on-site pharmacy when it has a pharmacy located on the physical premises of the registrant's registered location.” Registrants must complete a disposal log (DEA Form 41) and maintain records onsite for a minimum of two years when disposing of expired or unused controlled substances. State boards of pharmacy may be able to provide additional local or state requirements that must be followed.