Three miners were killed when they plunged down an airshaft in Indiana. And, with six miners trapped underground for several days in Utah’s Crandall Canyon, the dangerous business of professional mining is once again highlighted.

Although statistically speaking, mining is much safer today than it was 30 years ago (242 miners died in accidents in 1977, compared to 72 in 2006), it’s still considered one of the most dangerous jobs in the U.S., according to statistics from the Mine Safety and Health Administration.

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In mining accidents, injuries are can be caused by collapsed walls, falling debris, and suffocation caused by the inhalation of dirt and other airborne particles, as well as carbon monoxide and methane gas poisoning.

In one of the worst mining accidents of modern times, 12 miners on a 13-member crew died of carbon monoxide poisoning following the Jan. 2006 explosion at the Sago mine in West Virginia. Officials say the poisoning occurred when the miners air bags failed.

The lone survivor, Randall McCloy Jr. miraculously lived despite inhaling carbon monoxide for 41 hours. A hyperbaric chamber was later used to remove the CO from his bloodstream.

Dr. Manny Alvarez, managing editor of health for Foxnews.com, said initially miners trapped from explosions or cave-ins are at risk of sustaining "crush" injuries. These can include injuries to the head, neck, abdomen and outer extremities.

Cave-ins sometimes can confine miners to small spaces that can result in a limited oxygen supply, as well as exposure to carbon monoxide.

"Carbon monoxide is very dangerous because it can quickly damage the lungs and other organs," said Alvarez. "Even if a person does survive exposure, CO also can permanently damage the brain, which is another major concern."

Confinement also can result in blood clots to the legs, which can travel to the heart or result in a pulmonary embolism in the lungs.

"This is the unfortunate incident that we witnessed with David Bloom, the NBC News correspondent who died of a pulmonary embolism when he was embedded with the troops covering the war in Iraq," said Alvarez.

At Crandall Canyon, in Huntington, Utah, officials have said there is no indication of carbon monoxide or methane in the mine. But the miners, who are trapped underneath at least 1,500-feet of rock, may have been injured in the collapse itself.

Government mine inspectors have issued 325 citations against the Crandall mine since January 2004, according to an analysis of federal Mine Safety and Health Administration online records. Of those, 116 were what the government considered "significant and substantial," meaning they are likely to cause injury.

This article was reviewed by Dr. Manny Alvarez