NBC Montana was tipped off by witnesses that federal investigators were there until at least 4 a.m. on Thursday. Federal agents could be seen going through the company’s building and taking items to a truck parked outside. EPA lead criminal investigator Bert Marsden said that the agency was looking into alleged “environmental violations” by USA Brass.

“We are investigating alleged violations of environmental law,” Marsden said on Thursday. “An investigation takes as long as it takes, and I can’t provide any details as it relates to that.”

“I can make a statement that there is no immediate threat to the public or the community at this time,” said Marsden.