Is it legal to sell synthetic urine to pass a drug test? Okay so this question is mainly just out of curiosity, but potentially could be an interesting business I'd like to explore.

So I need to pass a drug test so went down to the smoke shop and bought a synthetic urine product. The product is adverised as "fetish urine". The somewhat discretely in the description allude to the fact it's "toxin free" and that it could be used for a drug test but it's advertised as fetish urine as opposed to clean urine to pass a test.

This had me curious if it's illegal to market or sell synthetic or real urine with the intent purpose of passing a drug test?

If it is illegal what law is it breaking?

As far as selling clean human urine I could see that being an issue for biohazard reasons, but if it's chemical synthetic urine could this be illegal?