The US Department of Labor report examined MSHA’s hotline responses from January 1 to March 30 looking at 410 complaints.

The report’s major recommendation was MSHA needed to set specific time limits for evaluating complaints and responding to the scene, rather than adhering to the current standard of "immediately" or "as soon as possible".

"We are not convinced that a standard of 'as soon as possible' is sufficient to drive evaluation and inspection performance," the report said. "These benchmarks are not quantified in terms of a number of hours or days."

MSHA spokesperson Dirk Fillpot told Associated Press that MSHA responded immediately to any report of hazards that posed imminent danger to miners and that MSHA would use the report’s recommendations to “help us target those areas deserving additional attention”

Of the 410 complaints examined, the report found 60% were handled the same day and 27% were addressed the next day. Of concern, 10% of complaints were delayed because the call came on a Friday, weekend or holiday.

The report also found that miners were generally aware of the MSHA reporting system, but some of the hotline’s deficiencies may have discouraged miners from using it.