The U.S. Attorney’s office said it has closed its investigation into a grain elevator explosion in Atchison, Kan. that killed six people in 2011.

In a statement from Attorney Tom Beall the U.S. Attorney’s Office has determined there is not sufficient evidence to support criminal charges against the owner, Bartlett Grain Company.

The incident took place in Atchison, on Oct. 29, 2011.  As we previously reported, investigators determined that the grain-dust explosion was an accident, but OSHA cited the company for safety violations.

The announcement does not dismiss pending enforcement actions by OSHA.