CHARLESTON, W.Va. - Federal inspectors have found more than 60 serious safety violations at Massey Energy operations since the explosion that killed 29 miners, adding to fallout from the disaster that includes a wrongful death lawsuit by one of the men's widows.

Inspectors visited more than 30 underground Massey coal mines in West Virginia, Kentucky and Virginia after the April 5 blast, according to records from the Mine Safety and Health Administration. The agency has tentatively blamed preventable accumulations of explosive methane gas and coal dust for the worst U.S. coal mining disaster since 1970.

The miner's widow accuses the company of a history of safety violations that amount to negligence in the first wrongful death lawsuit over the explosion, which she filed Thursday.

Investigators were reviewing records from the site of the blast and waiting for dangerous gases to be ventilated before going underground at the Upper Big Branch mine. It will probably be another week until investigators can safely go in, MSHA Administrator Kevin Stricklin said.

To tally violations at other Massey sites, The Associated Press checked inspection records for all of the company's approximately 70 underground coal mines in the U.S. from April 5 through Thursday. Mines operated by other companies also were inspected during the same period.

Stricklin said the MSHA hasn't been disproportionately targeting Massey since the blast, nor has it increased the pace of inspections. He did say inspectors have responded to hazard complaints at two Massey mines.

"We're just going about our regular business," Stricklin said. "I didn't give any instructions to go and look at Massey mines."

Still, Stricklin sharply criticized the company for violations found in the last 10 days.

The violations include conveyor belt problems at Massey's Aracoma Alma No. 1 mine in West Virginia, where a belt fire killed two men in 2006.

"I'm very disappointed," Stricklin said. "You would think that personnel associated with Massey would be really more careful."

The company's Solid Energy No. 1 mine in Kentucky was cited for allowing coal dust to pile up on three occasions since the explosion.

"That's very troubling," Stricklin said. "Pitiful."

Mines are required to keep methane well below explosive levels with sophisticated ventilation systems and control coal dust by keeping it from piling up and covering it with noncombustible material.

Stricklin has told district managers to look more closely at all mine ventilation systems and the buildup of methane, and to move rock dusting surveys to the front end of the quarterly inspection.

Stricklin said he was embarrassed the industry wasn't able to prevent the Upper Big Branch tragedy.

"An explosion of this magnitude basically sends us back 40 years. All explosions are preventable," he said.

Massey is facing its first wrongful death lawsuit over the blast, filed by Marlene Griffith in Raleigh County Circuit Court. The lawsuit also targets Performance Coal, the Massey subsidiary that operated the underground mine.

The lawsuit claims Massey's handling of working conditions at the mine, plus its history of safety violations, amounted to aggravated conduct that rises above the level of ordinary negligence.

Griffith and her husband, William Griffith, were planning to celebrate their 33rd wedding anniversary April 30, the lawsuit said.

Mark Moreland, a Charleston lawyer representing Griffith, said that William Griffith was concerned about safety in the mine and had avoided serious injury during a rock fall there a week before his death.

"He told his wife on more than one occasion that if anything happened to him in that mine, that she needed to get a lawyer," Moreland said Friday.

Massey did not immediately respond to requests for comment Friday on the lawsuits or the violations.

The West Virginia Office of Miners' Health, Safety and Training started its own safety sweep of the state's nearly 200 underground mines Friday. Administrator Terry Farley declined to say whether the agency is targeting Massey.

MSHA issued the recent citations while conducting spot checks and routine inspections at the Massey operations.

Agency records show the problems were not universal; several Massey mines weren't cited at all after the inspections.

Among those that came up clean is Massey's Tiller No. 1 mine in Virginia. Federal inspectors had warned Massey to improve safety at the mine last fall or face heightened enforcement for a pattern of serious violations.