Clean air groups are making good on a promise to sue Kennecott Utah Copper over air pollution.
The groups say Kennecott is kicking up too much dust at its Bingham copper mine and should curtail operations.
They say Kennecott is violating the federal Clean Air Act even though Utah's pollution regulators have allowed the company to significantly ramp up mining production.
The federal lawsuit was filed Monday by Utah Moms for Clean Air, Utah Physicians for a Healthy Environment and WildEarth Guardians.
Kennecott says the groups' claims are without merit and that it isn't violating pollution standards.
The Utah doctors say Kennecott is responsible for a third of the air pollution throughout Salt Lake valley, which was rated moderate on Monday. That rating means sensitive people shouldn't exercise vigorously outdoors.