Authorities said that two workers were killed at the North Carolina waste recycling facility on Sunday.

The cause of death for these workers, who were working at Valley Protein Inc. in Fayetteville was not immediately known. They were not identified by the Cumberland County Sheriff’s Office.

A sheriff’s spokesperson said that the couple were unresponsive on Sunday after they were called to the facility at 1: 32. Major crime detectives were conducting an investigation, authorities stated.

The Virginia company that processes waste from poultry processing plants, slaughterhouses and supermarkets did not immediately respond when we asked for comment.

Valley Protein has more than twenty-six facilities across the United States, with most of them located in the Southeast and mid-Atlantic.

Tim Stelloh is a reporter for NBC News based in California.