Eight members of the Canadian Forces failed drug tests and were kicked off HMCS Charlottetown prior to the ship's deployment to the waters off Libya in March, a navy spokeswoman said Friday.

The sailors were replaced before the ship sailed out of Halifax Harbour in March, Lt. Heather McDonald told CBC News. She said the ship's overall mission in Operation Mobile — helping the NATO-led effort to enforce a no-fly zone — was not affected.

"Forty-eight hours prior to HMCS Charlottetown deploying as part of Operation Mobile, safety-sensitive drug testing was conducted on all 235 crew members," said McDonald.

Of the 235, nine tested positive for illicit drugs, she said. One person was taking legally prescribed medication and remained on HMCS Charlottetown.

The navy did not specify the nature of the drugs found in the testing.

"The Canadian Forces have a strict policy in place to deal with the use of illicit drugs and it's due to implications on operational readiness, the safety of members and even the public. It even affects cohesion and morale," McDonald said.

"We do have a strict policy, and these members were removed and replaced, and the reviews are underway."

Drug testing before the navy's last two deployments revealed a higher number of sailors who tested positive for drugs than HMCS Charlottetown, said McDonald.

"The percentage was about 3.4 for this one and the other deployment was just over four per cent testing positive," she said, adding that it equals about 11 or 12 sailors.

McDonald said results of mandatory drug testing before a mission cannot be used to lay criminal charges, but the results will be used for administrative penalties.

Those penalties could include counselling, probation and dismissal from the Canadian Forces.