YOKOSUKA NAVAL BASE, Japan — The Navy is stepping up its "zero tolerance" posture toward illegal drug use with an immediate ban of urinalysis-defeating products, according to a Navy message Tuesday.

The purchase, possession, introduction, distribution or use of any product or device of any kind that is used to falsify urinalysis tests is prohibited, according to the message.

Numerous products are on the market and countless Web sites are devoted to helping people fraudulently pass drug tests.

Yokosuka’s legal services officer, Lt. Jonathan Flynn, said products specifically designed to defeat a urinalysis aren’t sold on base. However, General Nutrition Centers, or GNC stores, like the one on Yokosuka, sell legal body cleansing and detoxification kits. Those products are not affected by the ban.

"I don’t think you can distinguish between the two," Petty Officer 1st Class Bill Stewart, Yokosuka Naval Base’s urinalysis coordinator, said of people who buy the products for legitimate detox and those who might buy them to beat a urinalysis. "Detoxification kits are popular with people really concerned about their health."

But Stewart thinks the way the Navy’s tests are conducted makes use of the banned products or devices nearly irrelevant.

"People aren’t notified of a urinalysis until the day of, so trying to use a product to defeat it last minute probably won’t be effective," he said.

Stewart said the simple fact that sailors know they’ll be tested eventually is the main reason illegal drug use is low.

"Testing small numbers more frequently is much more of deterrence than testing big groups occasionally," he says. "You have people that statistically try to beat the odds, but the fact is, eventually their number will come up."