Five workers were reportedly injured in a explosion at the Amalgamated Sugar Company sugarbeet processing facility in Nampa, ID on Monday.

The blast occurred in a sugarbeet pulp steam dryer inside the plant at about 7:45 am, according to coverage by KTVB. A company official told the news station that the workers were donning fire protection gear when the incident happened, as it is part of the proper procedure for opening the equipment.

Four workers were treated at the plant and another worker was taken to an area healthcare facility. Spokesperson Jessica Anderson described the nature of their injuries as “very minimal” in an account by the Associated Press (AP).

Amalgamated Sugar is looking into the cause of the explosion and expects the US Department of Labor’s Occupational Safety and Health Administration (OSHA) to open an investigation was well, Anderson said in a Idaho Stateman article

The company, the second largest refiner and processor of sugar derived from sugar beets, in the US, produces industrial sugar, White Satin brand sugar, and animal feed products, according to its website. Amalgamated Sugar operates three sugar processing plants in Idaho, including the Nampa location.