MUNCIE, Ind. (AP) — Indiana regulators are drafting rules intended to cut the flow of the nutrient-rich element phosphorous into the state’s lakes to reduce algae blooms and other water quality problems.

Algae fed by high phosphorous levels can give surface waters a greenish cast and cause fish kills. This spring, an algae bloom on a reservoir near Anderson left the tap water in that city and nearby Indianapolis with an unpleasant, musty flavor and smell for days.

Blue-green algae sustained by phosphorous can also release toxins that can cause diarrhea, vomiting or nausea in boaters and swimmers.

Phosphorous is found in lawn fertilizers, human and animal waste and other sources.

The nutrient was barred in laundry detergents decades ago. But the state has been slow to impose new rules because of how much it would cost to upgrade sewage treatment plants to comply with phosphorus discharge limits, said Lenore Tedesco, director of IUPUI’s Center for Earth and Environmental Sciences.

“The state has dragged its feet for a long time,” she said. “Now I think they are moving forward.”

Indiana’s limits on the nutrient for the state’s lakes are expected to take about 18 months to draft, Bruno Pigott, an assistant commissioner at the Indiana Department of Environmental Management, told The Star Press.

The rule would affect sewage treatment plants upstream of lakes, but IDEM has not yet determined how far upstream of a lake a wastewater treatment plant may be regulated.

John Goss, director of the Indiana Wildlife Federation, said during a recent blue-green algae symposium in Indianapolis that Indiana’s wastewater treatment plants would need billions of dollars in improvements to help reduce nutrient pollution from urban areas.

While agriculture is an even larger source of phosphorus pollution than urban wastewater treatment plants, “agriculture is exempt from almost everything” Tedesco said. “They have a get-out-jail-free card.”

Barry Fisher, an agronomist for the Natural Resources Conservation Service, said at a recent symposium on blue-green algae that it should be remembered that much of Indiana is cropland.

“Compared to a lawn in the city, cropland is part of a business, and this business is dependent on yield, and yield is dependent on good fertility levels in the soil,” he said.

One of the easier steps to slow nutrient pollution would appear to be to ban or cut back on phosphorus in lawn fertilizer.

Lawmakers attending the recent symposium didn’t think there was enough support in the state Legislature to ban phosphorus in lawn fertilizer.

But the lawn care industry already is moving in that direction.

“I haven’t used phosphorus for two years in my program,” said Bob Avenius, regional technical manager for TruGreen Lawn Care. “We treat 30 percent of the lawns. Homeowners treat the other 70 percent.”