A Navy tradition will end at midnight.

By order of the Navy's top admiral, smoking will no longer be allowed on submarines. The smoking lamp will be no more.

A study convinced Navy brass that nonsmokers were being subjected to too much secondhand smoke despite onboard air purification systems.

The change was announced in April -- time for sailors in San Diego and at other submarine bases to take smoking-cessation classes or get nicotine gum or patches. The Navy estimates that 40% of its submariners are smokers.

"We push our crew every day, 12 to 18 hours a day," said Navy Master Chief Petty Officer Robert McCombs, engineering department boss on the ballistic sub Rhode Island. "Smoking is how they relax. Some people are saying they don't want to stay on subs because they can't smoke."

-- Tony Perry in San Diego