Three investigations of the 2010 disaster that killed 29 men at the Upper Big Branch Mine in southern West Virginia have concluded outrageous violations of basic safety rules were to blame.
Criminal investigations were launched and are continuing, with some mine foremen and company officials the targets. Alpha Energy, which bought the mine's former owner, Massey Energy, agreed to a $210 million civil settlement over the tragedy.
But federal mine regulations are supposed to be enforced by the Mine Safety and Health Administration. Included in some reviews of the Upper Big Branch explosion have been accusations the agency did not do its job.
An internal review of MSHA activities regarding the mine was conducted - but the agency has not yet released a report on it, months after the last of three general investigations was concluded.
Investigations have made it clear wrongdoing at Upper Big Branch often was devious enough it would have been very difficult to uncover.
But another concern has been voiced about MSHA's activities. It is that even when violations are uncovered, the agency sometimes does not impose penalties severe enough to deter future misbehavior.
Obviously, effective enforcement of health and safety rules is critical in keeping mines as safe as possible.
How well did MSHA do in enforcing the rules at the Upper Big Branch Mine? More important, are changes needed to make enforcement more reliable at mines in the future?
Answering those questions and others was supposed to be the purpose of MSHA's internal review of the disaster. Again, however, months after other reports on the tragedy were released, the agency's investigation of itself has not yet been forthcoming.
It appears MSHA has had enough time to conclude at least a preliminary internal review. It should either be released soon, or officials should issue a statement explaining why it has been delayed.