Starting this June, don't look for antibacterial soap in state government bathrooms.

State agencies have been ordered to stop buying products that contain triclosan, a microbe-killing chemical used in everything from plastics to cosmetics to dish soap — but which converts to an environmental toxin after it goes down the drain.

Monday's announcement by the Minnesota Pollution Control Agency comes as debate about antibacterial products is intensifying at the state Capitol. A bill banning triclosan's use outside of medical settings is expected to be introduced this week, and the Legislature will conduct a hearing Tuesday on the pros and cons of the chemical.

The steps reflect concern over recent research showing that triclosan toxins have been accumulating steadily in the bottom of many of Minnesota's lakes and rivers, after years of being discharged from water-treatment plants.

Conservationists have expressed growing concern that triclosan can damage the naturally occurring bacteria, microbes and algae that form critical links in the natural food chain, and that when exposed to chlorine in the treatment process and sunlight in water, it converts to a potential carcinogen. In laboratory studies, it's been shown to interfere with reproduction in some aquatic animals.

While there is no scientific evidence that the substance is harmful to consumers who are exposed through the use of household products, federal health agencies have accelerated their review of its safety in the wake of studies that show it accumulates in the body, is found in 75 percent of the population and also in breast milk.

The Food and Drug Administration concluded in 2010 that products with triclosan are no more effective than plain old-fashioned soap and water, so state officials said Monday their decision wasn't difficult.

"There are alternatives, and they are at the same price," said Cathy Moeger, sustainability manager for the Pollution Control Agency. "If it has an environmental benefit, why not do it?"

Hearing Tuesday

Officials from the American Cleaning Institute, an industry group, say there is no evidence that triclosan is a risk to human health or the environment.

"We are really disappointed in the announcement," said Brian Sansoni, spokesman for the council. "Primarily because it contains so much misinformation about triclosan."

He said the council's representatives will attend Tuesday's hearing and present information about triclosan's safety and benefits. Products containing the chemical have a long history of safe and effective use, he said. "At least [the state] could have waited until that discussion was had," he said of the hearing.

But Trevor Russell, watershed program manager for Friends of the Mississippi River, said the decision, signed by Gov. Mark Dayton, sends an important signal.

"When the [state] steps up and says we are going to stop using, it builds public support," he said.

It also raises awareness about something that most people don't even know they are using, Russell said. He added that he's even found soap with triclosan in the office bathrooms of the environmental groups that are pushing for a statewide ban.

"A lot of people don't know that it exists, and they don't really know how they are coming in contact with it," he said.

Triclosan is included on the package ingredient list of products that contain it. Plastics or fabrics that contain triclosan are sometimes marketed as Microban or Biofresh.

The state and about 100 school districts and local governments together buy about $1 million worth of cleaning products annually through joint purchasing contracts, though not all of that is for products that might contain triclosan. But starting this year, the list of choices will include only those that don't have it.

Monday's announcement is part of a broader state sustainability initiative — signed by Dayton — that also includes plans to reduce the use of bottled water and make printing and copying more efficient. In past years, the state has also used its buying power in other ways, including mandating the use of recycled print cartridges in state offices.

Banned elsewhere

Concern about the use of triclosan is growing globally. Japan has banned the sale of consumer products with the chemical, Canada is considering it, and the Kaiser Permanente medical system in California has stopped using them its hospitals. The consumer product giant Johnson & Johnson is phasing out its use as well.

In the environment, triclosan becomes a dioxin, a family of environmental contaminants linked to a variety of health risks, from cancer to hormone disruption, and which persist in the environment for years. They once came largely from industrial sources such as paper pulp mills and garbage incinerators, but increasingly stringent regulations have greatly reduced their emissions.

The recent study of triclosan in eight Minnesota lakes, conducted by scientists at the University of Minnesota and the Science Museum of Minnesota, found that triclosan and the dioxins it forms have increased in sediment while other kinds have decreased. In short, even though the water-treatment process removes most of the triclosan, antibacterial products are now the primary source of dioxins in the lakes and rivers.