Within several days, there was another fatality, this time in Utah.

The string of back-to-back-to-back, highly publicized tragedies has shaken coal-producing states and the No. 2 coal-producing nation to the core. Anguished families are wondering what went wrong, politicians are demanding new laws, and labor leaders are asking why technology has largely passed them by.

But coal mine accidents in China, the world's top producer, kill an average of 16 workers a day.

''Overall, U.S. mine health and safety - it's still the envy of the world,'' says Raja Ramani, a professor of mining engineering at Penn State University.

In many ways, experts say the U.S. coal industry is the model to emulate, with safety laws on the books, a federal agency charged with enforcing them and well-funded, health-oriented research. But a false sense of security may have set in as deaths plummeted - from 260 in 1970 to 22 last year.

With fewer people dying, coal companies had little reason to change what they were doing, says Larry Grayson, mining engineering professor at the University of Missouri-Rolla. With no financial incentive, manufacturers of safety equipment had no motivation to modernize. And with little proof that emerging technology would work as promised, most companies were reluctant to invest.

Opportunities to take advantage of the latest in safety technology were lost, from emerging underground communications systems and tracking devices to chambers where miners with no hope of escape could hunker down and await rescue.

The wake-up call could have come Sept. 23, 2001, when 13 men died in an underground explosion at the Jim Walter Resources No. 5 mine in Alabama, but then, attention was still focused on the terrorist attacks that had claimed thousands of lives in New York and at the Pentagon.

Until Jan. 2, few people thought about the 42,000 U.S. miners who toil underground, digging coal to produce half the nation's electricity. But that day, an explosion at International Coal Group's Sago Mine trapped a crew of 13 hundreds of feet underground. Twelve men died, and the one survivor must learn to walk and talk again.

The television satellite trucks had barely left West Virginia when a second accident killed two miners in a conveyor belt fire at Aracoma Coal's Alma No. 1 mine. Days later, two more men died in separate accidents.

Now, for the third time in a century, tragedy in West Virginia could reshape regulations.

The deadliest accident in U.S. mining history occurred Dec. 6, 1907 in Monongah, when an explosion killed 361 men. It was one of several that year and helped prompt Congress to act on President Theodore Roosevelt's call for creation of the U.S. Bureau of Mines.

Slowly, the number of deaths began to dwindle - from 1,619 in 1930 to 325 in 1960.

Then, in November 1968, an explosion at the Farmington No. 9 mine killed 78 men. This time, Congress passed the Mine Health and Safety Act of 1969, creating the federal Mine Safety and Health Administration.

Sago led West Virginia lawmakers to pass a new mine-safety bill in a single day, requiring companies to use communication and tracking devices, store extra air packs underground and report accidents within 15 minutes. Other states are debating similar measures.

West Virginia's congressional delegation wants similar federal legislation, calling for tougher fines and the shutdown of mines that habitually ignore safety.

MSHA is following suit, announcing it will use an emergency rule to require both extra oxygen caches and faster notification of accidents, as well as ''lifelines'' on all mine escape routes.

But Ramani, from Penn State, says any new law should be based on proof that technology can perform as lawmakers demand. ''A law cannot be based on good intent,'' he says.

For the improvements so far, coal companies can claim some of the credit.

J. Davitt McAteer, former head of MSHA, acknowledges the corporate mind-set today is ''entirely different'' than before 1969.

''It was acceptable to kill 200 people a year then,'' he says. ''This is the 21st century, and people do not expect to have death and carnage in the mines at this level.''

But death rates also fell because mechanization put fewer people at risk, and production began to shift to less dangerous surface mines.

With the price of oil and natural gas rising, U.S. companies will produce a record 1.156 billion tons this year, a 3.2 percent increase over last year, predicts the Washington, D.C.-based National Mining Association.

That means the number of underground miners has grown, from 40,123 in 2003 to 42,016 in 2004, while the number of surface miners went from 30,795 to 31,785, according to the Energy Information Administration.

McAteer says it is vital to provide them better training and new safety equipment, as many Australian mines have done.

''The industry itself has to have a change of heart and say, 'We want to improve,' '' he says.