A heater cart at Mariner Construction's asphalt plant caught fire Wednesday.

Workers at Mariner said a pump they were using in the asphalt-making process quit working, so they looked around. They said they saw smoke, looked closer and realized that the heater cart was on fire.

The heater cart heats the oil that is added to rock to make asphalt, said Mike Newman, plant operator.

The heater cart is at the rear of the asphalt operation.

"That's why it's on the back, in case it does start on fire," said Cameron Wolf, a Mariner worker. "We caught it right away when it started on fire."

Wolf said they were going to try to put the fire out but realized it was too big.

Newman said they had been making asphalt for Burleigh County for a project near Baldwin. The fire didn't allow the crew the rest of the day off, because they had to fix the damage, he said.

"Now we won't be in the air-conditioned shack anymore,"Newman said.

Greg Mariner, owner of the company, said they weren't completely sure how the fire started, but they think something must have sprung a leak. It wasn't the first time the heater cart has caught fire, he said.

"It's happened one other time to us," he said.

Mariner said he was unsure how much the damages would cost.

The Bismarck Rural Fire Department responded and put out the fire at 1771 W. Cavalry Ave. Chief Al Klein said firefighters were foaming the area to cover any petroleum.

All of the tanks around the plant have petroleum-based products, so it was important to get the fire out before any other equipment could catch fire, he said.

"Fortunately, the wind was in the right direction, blowing to the north," Klein said.

Plenty of firefighters were on standby at the fire that started up on the hottest day yet this summer. Fighting fires in full gear on such a warm day requires plenty of fluids, Klein said.

"It's extremely hot inside the suits," he said.

The best bet is to "work slow and take lots of breaks,"he said.

(Reach reporter Jenny Michael at 250-8225 or jenny.michael@;bismarcktribune.com)