Crews in hazmat suits are seen outside the New Balance factory in Skowhegan. Credit: Natalie Williams / BDN

A chemical in the glue used to attach soles to shoes could be the reason employees at the New Balance factory in Skowhegan on Thursday began reporting symptoms including eye irritation, difficulty breathing and burning, according to the Waterville Morning Sentinel.

Skowhegan Fire Capt. Rick Caldwell told the Waterville newspaper on Friday that the chemical 2,5 Dimethoxy-4 chloroamphetamine, commonly known as DOC, is a component in the shoe glue.

“Because they use this glue, there’s obviously some DOCs that come off, but for some reason, evidently, there was higher levels yesterday and they’re thinking that’s the reason,” Caldwell told the Morning Sentinel. “At this point, it’s going to be more of an investigation or follow-up to see what happened.”

About 30 employees reported experiencing the symptoms on Thursday afternoon, prompting the Boston-based shoe manufacturer — which has three Maine factories — to evacuate the plant and shut down operations. About 70 employees were decontaminated after the chemical incident.

Five people were taken to Redington-Fairview General Hospital in Skowhegan due to the chemical exposure, and were released Thursday evening.

A New Balance spokesperson said the company expected to reopen the factory after the weekend.