ANCHORAGE — A federal judge this week allowed an environmental lawsuit involving coal-dust emissions in Seward to proceed in court.

In a 27-page ruling signed on Monday, Anchorage federal District Judge Tim Burgess denied motions by the Alaska Railroad and Aurora Energy Services to dismiss the case.

Two environmental groups are suing the companies over coal dust and debris that ends up in Resurrection Bay due to operations at the coal export terminal at the downtown Seward port. The railroad owns the terminal and Aurora, a firm affiliated with the Usibelli Coal Mine, operates it.

The groups, Alaska Community Action on Toxics and the state chapter of the Sierra Club, say the coal that ends up in the bay violates the Clean Water Act and has been a public health hazard in Seward for many years.

The companies argue they can't be sued under the Clean Water Act because the state is regulating coal dust from the Seward terminal under its air pollution rules.

In his ruling, Burgess said he might eventually be convinced that the coal emissions are not covered by the Clean Water Act, but at this point, "the Court cannot agree that the mere fact that the pollutants travel some distance through the air defeats liability."