Federal officials say they anticipate finishing by late 2014 a risk study to guide the cleanup of a contaminated Montana mining town where hundreds have died from asbestos exposure.
    
That comes after a panel of scientists recently backed a draft study that said even minuscule amounts of asbestos from a W.R. Grace & Co. vermiculite mine outside Libby, Mont. can lead to lung problems.
    
The risk study will determine when Libby's cleanup can end.
    
It has so far has cost more than $447 million over more than a decade.
    
Environmental Protection Agency toxicologist Deborah McKean says the agency will complete the study earlier if it can, possibly by the end of this year.
    
But she says the EPA first must do additional work recommended by its Science Advisory Board.