The court reinstated the class-action lawsuit against Grain Processing Corp., which operates a plant that turns corn kernels into products ranging from corn syrup to ethyl alcohol. The plaintiffs' claims of nuisance, negligence and trespass are not barred by the federal Clean Air Act or state rules governing air emissions, Justice Brent Appel wrote in a 6-0 decision that was applauded by environmentalists but criticized by business interests.

A regional economic force, the company buys $400 million in corn from farmers annually and is one of the area's largest employers.

But Muscatine residents have complained for years that it spews harmful chemicals into the environment that get blown onto their homes, yards and cars. The lawsuit, filed on behalf of up to 17,000 residents who live within a 3-mile radius of the plant, contends the pollution undermines their ability to enjoy their property and causes metals in everything from swing sets to air conditioning systems to corrode.