MISSOULA, Mont. -

The Blackfoot and Clark Fork rivers near Missoula are now reopened after Missoula County health officials determined that the chemicals that spilled from a semitruck wreck into the Blackfoot River east of Bonner Tuesday morning are highly diluted and not hazardous.

Montana Fish, Wildlife & Parks closed a 23-mile stretch of the Clark Fork and 13-mile stretch of the Blackfoot River while crews assessed the spill and potential public safety concerns.  Officials found the amount of chemicals spilled was small enough that it quickly dispersed and diluted.

The driver of the truck told the Montana Highway Patrol his right front tire blew as he was rounding a corner at about 9:15 a.m. Tuesday. The truck ended up on its side.

Missoula Rural Fire Acting Battalion Chief Paul Finlay says the chemicals appeared to be coming from containers of aluminum sulphate and diethanolamine, which are used in making detergents.

Crews placed a boom on the river to contain the spill and worked to plug a drainage pipe that was carrying the spill from the ditch into the river.