A parking lot at Clinton Reservoir Water Treatment Plant looked like a large charcoal grill Monday after spilled carbon ignited.

The incident occurred about 10 a.m., when workers for a company – Calpacific – were unloading carbon from a semitrailer into an underground storage tank in a back parking lot of the plant, 2101 Wakarusa Drive. A hatch clasp on the truck broke, allowing the carbon to spill, said Jeanette Klamm, utilities program manager with the city of Lawrence.

The city’s water supply was not in jeopardy during the incident, she said.

“It’s kind of like a charcoal grill,” Dave Wagner, city of Lawrence utilities director said, describing the fire that covered an area measuring about 30 yards across.

Hazmat crews remained at the plant for more than three hours to handle periodic re-ignition of the carbon.

After investigating, Lawrence Fire Chief Mark Bradford said he didn’t know what caused the fine, powdery carbon to ignite.

Two Reddi Services trucks vacuumed the spilled carbon Monday afternoon, a plan that state officials had approved, Bradford said.

The spill forced emergency crews to close Wakarusa Drive between Clinton Parkway and 15th Street for a short time Monday morning.

Carbon is used to control the taste and odor of the city’s drinking water, Klamm said.

“Basically it gets rid of the fishy, muddy taste that would be in the water typically,” she said.