WASHINGTON — The Nuclear Regulatory Commission is investigating a Montana company for apparent violations of handling radioactive materials and possible intimidation of employees.

The federal agency is reviewing activities at Mattingly Testing Services, Inc. in Molt, 20 miles northwest of Billings. The company uses Iridium-192, a radioactive material, to conduct “industrial radiography,” or the inspection of metal structures for cracks or other defects. The process is similar to an X-ray.

In a notice published in the Federal Register Jan. 30, the commission said inspectors found apparent violations on a November 2007 visit. During a follow-up inspection and investigation, federal employees were informed senior management at the company had discouraged employees from speaking with them, the commission said.

“The NRC is concerned that an environment exists within Mattingly Testing’s workplace that could inhibit employees from raising safety concerns,” the notice said.

The agency said their ongoing investigation has indicated the company’s “control of licensed material” at temporary job sites is not in compliance with their regulations. In addition, “Mattingly Testing’s senior management has apparently caused employees to engage in activities that are in violation of NRC regulations and orders,” the notice said.

“This information demonstrates a lack of management control and supervision over licensed activities, raises questions as to whether Mattingly Testing will provide complete and accurate information to the NRC,” it read.

The company’s owner and president, Mark Ficek, said Monday that managers have not discouraged employees from talking.

“No member of Mattingly Testing Services has ever threatened any employee or discouraged any employee from talking to the NRC,” he said. “We are working with (the agency) to ensure than all Mattingly Testing Services employees are free to bring to our attention any safety concerns.”

He declined to detail what those concerns might be.

Greg Morell, a regional coordinator for the NRC, also said he could not detail the apparent violations, citing national security.

“If there’s a potential weakness, we wouldn’t want anyone to know about it,” he said.

At the same time, Morell noted the concerns were not significant enough to shut the company down. The agency has requested more information from the company, including its plans to ensure the workplace is safe. The NRC said it needs that information to determine if the company’s license should be modified, suspended or revoked, or if other enforcement action needs to be taken.

Iridium-192 is a man-made metal that is used industrially and in medicine that treats certain cancers. According to the Centers for Disease Control and Prevention, exposure could increase the risk for cancer because of its high-energy gamma radiation. External exposure could cause burns, radiation sickness or even death.

There does not appear to be any threat to the general public, however.

“If we thought for one second there was cause to shut them down we’d shut them down immediately,” he said.