For years, people in Biddeford have complained that they grow nauseous during backyard barbecues because of chemicals falling from the incinerator smokestacks that rival the town’s church steeples in height.

In Hampden, concerned residents wonder whether the odor coming off the mountainous landfill is a sign of something more ominous.

And in Old Town, people worry about losing their clean water or their property value if the local landfill starts accepting truckloads of new waste.

Increasingly, state and federal regulators are taking these concerns seriously, and introducing legislation that goes beyond the capacity question to reduce the toxicity of trash going into our landfills and incinerators.

“We’ve reached the point where our goal is to reduce contaminants,” said Paula Clark of the Department of Environmental Protection.

Environmentalists often discuss “toxic chemicals,” but legally, the word “toxic” has no meaning. Rather, waste is deemed hazardous, general, or special.

Special waste is a catch-all term that includes construction debris, asbestos, old appliances and the ash from incinerators. Maine has no hazardous waste facilities, and just two of the state’s landfills – Norridgewock and Hampden – accept special waste. Old Town would be the third.

But even municipal landfills handle more than 30 million pounds of household paints, solvents and pesticides that, were they used by a business, would be considered hazardous waste.

Each year, Maine’s solid waste stream also accepts about 18 million pounds of vinyl – the ubiquitous plastic of pipes, shower curtains and credit cards – which can release dioxin into the atmosphere when incinerated. And thousands of pounds of mercury and lead sneak into dumps and incinerators in batteries, thermometers, fluorescent bulbs and household electronics.

When these materials are burned, chemicals – many of them believed to be harmful – can escape into the atmosphere. Even when buried in landfills, chemicals can leach into groundwater or escape into the air.

“It’s really hard to manage toxics when they’re incorporated into products,” said John Dieffenbacher-Krall of the Maine People’s Alliance, an environmental and public health advocacy group.

But companies are beginning to get the message from states such as Maine, which is at the national forefront in reducing these waste streams, said Mike Belliveau, who heads a Maine lobbying group called the Environmental Health Strategy Center.

. In recent years, Maine has banned the landfill burial and incineration of mercury products, and won a legal challenge to its law requiring car companies to collect and recycle mercury switches. Beginning in 2005, it will be illegal to throw away products containing mercury.

. Last year, legislators approved a law to phase out the sale of pressure-treated lumber that contains arsenic. DEP also is drafting a plan to stop the treated wood’s incineration and burial in unlined construction debris landfills.

. As of 2006, it will be illegal to throw away computer monitors and televisions containing cathode ray tubes, as each can contain 5 to 10 pounds of radiation-shielding lead. Lawmakers are currently considering a law that would require manufacturers to take responsibility for recycling their products.

. Legislators also are considering a ban on the sale of chemical flame retardants that are used to treat fabric and included in the plastic that makes up computers and wire sheathing. Recent studies have found the chemicals in peregrine falcon flesh and human breast milk.