Two Mars Wrigley workers in the United States have been rescued after falling into a vat of chocolate while performing maintenance.

The situation unfolded on Thursday, June 2, at the Mars Wrigley plant in Elizabethtown, Pennsylvania, but officials have not said how the workers—who work for an outside contracting firm—came to be stuck.

Local news reported that the chocolate in the tank was about waist-high, and that the workers were unable to get out on their own. Emergency crews freed the pair by cutting through the bottom of the tank.

Both patients were transported to the hospital, Lancaster County 911 Dispatch assistant supervisor Nick Schoenberger told CNN. “One patient was transported by ground and one person was transported by helicopter,” Schoenberger said.

The extent of their injuries is unknown and a Mars Wrigley spokesperson told CNN: “We are actively managing the situation and our primary focus is supporting emergency teams on site.”

According to an incident report filed the day of the accident, a police officer who was called to the scene “learned that 2 males were cleaning out a chocolate container and the chocolate sludge (called liquor, a mix of chocolate beans and butter) had hardened around their legs.”

One man on the scene told the officer that workers are usually placed in harnesses and lowered into the containers, however a firefighter on the scene told the officer that only one of the men had a harness on.

The federal Occupational Safety and Health Administration is investigating the incident.