LEWISTOWN – Property owners are teaming with Montana Fish, Wildlife & Parks to try to force Monsanto Chemical Co. to pay millions to clean up chemicals contaminating a blue-ribbon trout stream here, but the company says the contamination is FWP’s fault.

PCBs, or polychlorinated biphenyls, a long-lasting pollutant, have tainted waters downstream from the Big Spring Trout Hatchery five miles south of here.

The PCBs were contained in the paint FWP used since the 1960s to paint raceways at the hatchery. Paint chips eventually made it into the creek, contaminating fish downstream. The hatchery’s raceways are concrete, rectangular-shaped pools where fish are reared.

A jury trial began Tuesday before District Court Judge Kurt Krueger on a claim by the state and area landowners that Monsanto should contribute up to $10.5 million to the creek cleanup and face punitive damages.

Monsanto didn’t make the paint the FWP used to paint the raceways, but it manufactured the PCBs used in it.

Attorney Torger Oaas, arguing on behalf of the landowners and the state, said evidence would show that Monsanto continued to sell PCBs to its customers even after it became known in the 1960s that they are harmful.

“Monsanto knew from Day 1 that paint containing this toxic and indestructible chemical was certain to get into the environment,” Oaas said.

Monsanto attorney Thomas Carney disputed Oaas’ allegations. He also said Monsanto “didn’t have anything to do with putting paint chips in to the creek.”