An environmental watchdog group that successfully challenged a proposal to exempt the oil and gas industry from water-quality regulations last year is shifting its focus to the maligned Cemex cement plant in Lyons, colorado (reports The Daily Times). Denver-based Colorado Citizens Campaign wants the cement company to adopt more stringent pollution controls at its plant and is knocking on doors in the area to ask for help.

The plant’s neighbors have questioned Cemex’s pollution-control practices and its plans to burn tyres for fuel, but CCC hopes to generate broader interest by arguing that the plant contributes to haze in Rocky Mountain National Park, group spokeswoman Kathleen Carlson said.

“That’s something everybody in Colorado takes a little bit of ownership in,” she said. “People are very passionate about this issue. In only a few weeks’ time, we’ve already generated 350 letters.”

CCC says Cemex is the largest industrial source of haze in Rocky Mountain National Park. They base their claim on a study by state health officials who identified 11 facilities — most of which were coal-burning power plants — as contributors to regional haze. CCC is focusing on Cemex in part because, of its proximity to the national park, Carlson said.

The Lyons Cemex plant repeatedly made local headlines in the past year. In April, a judge validated a permit allowing Cemex to fuel its cement kiln with discarded tyres. Tire burning could begin later this year, according to plant officials. In September, state regulators accused the company of failing to properly control emissions from its kiln and threatened the company with up to $15,000 a day in fines. The company is disputing the allegations.