U.S. Chemical Safety Board investigators called on the Labor Department to propose broad new standards on combustible dust within a year.

The department's Occupational Safety and Health Administration has been working on the combustible dust issue for years, but as recently as July OSHA officials said they were "not able to project an estimate for when we will publish a proposed standard on combustible dust."

"We would like OSHA to come out with a timetable to deal with this," board chairman Rafael Moure-Eraso said in an interview Wednesday afternoon.

Moure-Eraso and other board members were in Gallatin, Tenn., Wednesday night for a public meeting where they were to release the findings of their investigation of a series of combustible dust incidents. Between January and May, three iron-dust flash fires at the local Hoeganaes Corp. powered metal facility killed a total of five workers.

CSB investigators have concluded that unsafe accumulations of iron dust were a factor in all three incidents at Hoeganaes, and that such dust is combustible and presents a "serious flash fire hazard."

A wide range of common combustible materials can explode in finely powdered form, including metals, wood, coal, flour, sugar, plastics and many chemicals and pharmaceuticals.

After an extensive investigation, the CSB issued a 2006 report that identified 281 dust fires and explosions that killed 119 workers and injured 718 others nationwide between 1980 and 2005.

In Wednesday's report, board investigators noted 17 other deaths in dust incidents the agency is examining, including three in a December explosion that killed three workers at the AL Solutions Inc. metals recycling plant in New Cumberland, Hancock County.

The AL Solutions facility recycles titanium and zirconium for use in the metals industry, and the new CSB report identified the December incident as involving "titanium powder."

Daniel Horowitz, a board spokesman, said CSB investigators believe there are similarities between the Hoeganaes incidents and the one at AL Solutions, including the failure to control accumulations of combustible metals dust.

In its 2006 report, the CSB urged OSHA to adopt a broad rule to protect workers in all sorts of industries from the potential dangers of combustible dust. So far, OSHA has not proposed such a rule. Instead, the agency is relying on what it says are stepped up training efforts and inspections.

But in their report Wednesday, the safety board said OSHA did not include the iron and steel mill industry classification -- covering plants like Hoeganaes -- in its national emphasis program for dust inspections.

Leni Uddyback-Fortson, an OSHA spokeswoman, said her agency "looks forward to reviewing the CSB report.

"Combustible dust explosions continue to be an area of high concern for OSHA," she said. "We will continue to inspect facilities under the combustible dust national emphasis program while also pursuing combustible dust rulemaking."

Reach Ken Ward Jr. at kw...@wvgazette.com or 304-348-1702.