Canada's armed forces issued orders Friday strictly limiting cannabis use among service members, just a month before the country legalizes the drug.
Soldiers will be banned from smoking or otherwise consuming the drug up to eight hours before reporting for duty.
The ban on usage will kick in 28 days before any deployment for personnel serving on submarines, planes or helicopters, or for those piloting drones, conducting high-altitude parachute drops or engaging in air traffic control.
"Traces of cannabis may remain in the human body for up to 28 days or more following consumption," the defense ministry said in a statement detailing the restrictions.
The ban on consuming the drug for eight hours before work at a military base applies both to uniformed and civilian members of the armed forces.
Any personnel due to handle weapons or explosives, participating in emergency services or driving military vehicles will be prohibited from consumption up to 24 hours before duty.
The statement on the armed forces website also listed signs of cannabis use that service members should look out for among their comrades, including "the smell of cannabis, glassy or red eyes, unusual talkativeness, slow reactions, inattention, lethargy, unsteady gait, poor coordination and anxiety."
Canada is set to become the second country in the world to legalize cannabis on October 17, following the example of Uruguay which legalized it in December 2013.
The military reminded its members that "cannabis consumption and possession remain illegal in most countries" and warned that service personnel "could be denied entry to these countries as a result of their cannabis consumption or involvement in the legal cannabis industry in Canada."
Failure to conform to the rules could lead to administrative or disciplinary measures, the armed force warned.