If you are at a materials science or physics lab, it can't be difficult to get.

> One of the elements used here is phosphorus (P) which is regulated by the DEA

I would have figured ATF. What drug can you synthesize with phosphorus? (EDIT: Apparently meth [1].)

[1] https://www.federalregister.gov/documents/2000/09/25/00-2455...

Hell, Sigma Aldrich will sell you LSD. Established labs have no trouble with lightly restricted drug precursors, they've done all the paperwork.

Seriously… elemental phosphorus is controlled by the DEA? The ATF I could maybe understand but the DEA… that’s just whacky.

Probably ATF, not DEA. DEA regulates controlled substances. ATF regulates explosives.