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 now includes the first wrongful-death lawsuit by a miner's widow.

Inspectors visited more than 30 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, Marlene Griffith, accuses the company in her lawsuit of a history of safety violations that amount to negligence, in the first wrongful-death lawsuit over the explosion, which she filed Thursday.

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

Investigators on Friday 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 before investigators can safely go in, MSHA Administrator Kevin Stricklin said.

Stricklin said that MSHA had not been disproportionately targeting Massey since the blast, nor had it increased the pace of inspections. He did say inspectors had responded to hazard complaints at two Massey mines.

"We're just going about our regular business," Stricklin said. Still, he 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. The company's Solid Energy No. 1 mine in Kentucky was also cited for allowing coal dust to pile up on three occasions since the explosion.

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