§ 102-74.400 What is the policy concerning the possession and use of narcotics and other drugs?
Except in cases where the drug is being used as prescribed for a patient by a licensed physician, all persons entering in or on Federal property are prohibited from—
(a) Being under the influence, using or possessing any narcotic drugs, hallucinogens, marijuana, barbiturates, or amphetamines; or
(b) Operating a motor vehicle on the property while under the influence of alcoholic beverages, narcotic drugs, hallucinogens, marijuana, barbiturates, or amphetamines.
https://www.ecfr.gov/current/title-41/subtitle-C/chapter-102/subchapter-C/part-102-74/subpart-C
Cocaine doesn't stay in the system for more than a few days.
That's assuming they're taking a break, lol.
You can do a hair test.
My old boss had a story. Life Insurance does a coke screen on all blood tests. Positive test is an automatic decline and you have a hard time getting coverage at all for the next 5 years and after that, if you can get it, will be highly rated for at least the next five. Client tested positive bit insisted he was clean; that the test was wrong and he needed a redo. So company offers him a hair test. The technician shows up. Guy had shaved his head, legs, etc. Except he forgot to ask, shall we say, for a Brazilian. Tech made him drop, he grabbed the down there hair...and the hair test was positive.