NASHVILLE (AP) - Federal rules to prevent accidents like the iron-powder-fed fireballs that contributed to five deaths at a Tennessee factory last year have been put on the slow track.

The move comes shortly after the agency investigating the Hoeganaes Corp. accidents in the Nashville suburb of Gallatin urged regulators to step up the pace of implementing safety standards.

Industrial dust fires and explosions from products like chemicals, plastics, metals and foods kill and injure workers every year.

The Occupational Safety and Health Administration began developing rules to control dust hazards in 2009, but officials have not said when they will complete the process.

Two weeks ago, OSHA took the item off its current agenda and made it a long-term action item.

OSHA says preventing worker deaths from dust explosions remains a priority.