MESA — A loaded coal train passing through Mesa derailed Monday evening, knocking about 30 cars off the track and sparking a major cleanup effort well into today.

There were no injuries to the two-person crew as about one quarter of the 125-car train left the track and tipped over, sending what witnesses described as "a haze of black smoke" into the sky.

The accident happened at 6:30 p.m. and within two hours, 40 personnel were dispatched to the small town in north Franklin County to work on the site through the night, according to BNSF Railway Co. spokesman Gus Melonas in Seattle.

BNSF brought in heavy equipment from Pasco, including front-end loaders and bulldozers, "to shove the derailed cars off to the side to enable the track crews to make the necessary track repairs," he told the Herald.

The derailment is blocking Manton Way, which leads to a grain elevator and at least one home on the north side of town, according to initial reports from witnesses.

Franklin County sheriff's Sgt. Jim Dickenson said the accident started at the railroad crossing at First Avenue and May Street.

The approximately 30 cars that fell onto their sides were about midway through the train and now appear to be destroyed, he said.

Dickenson, who responded to make sure no one was injured in the destruction, said he remained on the scene to provide crowd control because there were a lot of spectators.

He said the department would be doing extra patrols around the site overnight to make sure no one was bothering the cleanup crews.

Dickenson added that the county roads department was called in to barricade the affected railroad crossing until that intersection is cleared.

Initial estimates are that the line could be opened as early as today.

Some coal spilled from the overturned cars and sent up a cloud of dust.

However, Melonas said there is no environmental threat from the derailment.

A company official was at the scene Monday night but had not yet determined a cause, he said.

The train originated in Powder River Basin, Wyo., and was destined for British Columbia.

"Approximately 30-plus trains operate on this line daily," Melonas said, adding that "some traffic will be rerouted via Wenatchee and the Seattle to Vancouver, Wash., route."

-- Kristin M. Kraemer: 582-1531; kkraemer@tricityherald.com