Giving up smoking may be a New Year's resolution for some, but all US sailors will now have to follow suit, as the US Navy moves to ban its crews from smoking aboard submarines starting Friday.

In a country where fights against Big Tobacco are common, troops deprived of fresh air and natural light for months were surprisingly allowed to smoke in submerged submarines. But no more, after a Pentagon study found the risks of second-hand smoke were severe in those highly confined spaces.

Submarine Forces Commander Vice Admiral John Donnelly ordered the ban aboard 73 US subs, citing health concerns.

"Our sailors are our most important asset to accomplishing our missions," he said in announcing the measure in April.

"Recent testing has proven that, despite our atmosphere purification technology, there are unacceptable levels of secondhand smoke in the atmosphere of a submerged submarine. The only way to eliminate risk to our non-smoking sailors is to stop smoking aboard our submarines."

About 40 percent of the 13,000 US submarine sailors smoke -- double the US national average.

The order comes 16 years after a ban on smoking in military buildings and installations, as well as aboard US Navy ships. Sailors are, however, allowed to smoke on the decks of surface ships.

US submarine sailors are also bracing for another major change with women being allowed to serve aboard submarines for the first time starting late next year or in early 2012.

British submarine sailors are allowed to smoke on board, while the French have banned the practice except on decks when the submarine is out of the water.

(c) 2010 AFP