Fire crews were dispatched to a dairy farm in Weld County on Wednesday evening for a "confined space rescue," the Southeast Weld Fire District said.

The deaths are being investigated as the possible result of exposure to toxic gas, but autopsies will be completed.

Six people are dead following a “dairy accident” on a farm in Weld County, Colorado. Emergency crews were dispatched to a “confined space rescue” on Wednesday evening, the Southeast Weld Fire Protection District announced on Thursday afternoon. There, crews “recovered six deceased individuals” from the space.