TV show teaches public about toxic wastes.

On a recent Tuesday night, the TV audience here could choose from the usual lineup, ''The A-Team'' and ''Three's Company,'' or tune in to a new option - ''The Great Waste Debate.''

In New York or Hollywood, a three-hour program about toxic waste would never get past a network executive's yawn. But this debate, sponsored by a local community group, was aired on the cable-TV system in this southeastern Massachusetts community.

The debate is part of a grass-roots effort in this state to educate the public about issues surrounding hazardous-waste treatment and disposal.

Since a comprehensive siting law for hazardous-waste treatment plants was enacted in 1980, four plants have been proposed in Massachusetts. All four have since been withdrawn, partly as a result of public outcry in towns where the plants were to be built. The most recent withdrawal came in June, when the California-based International Technology Corporation decided not to proceed with plans to build a vast facility in western Massachusetts.

In response to the failure to build a facility, state officials are working with community groups, environmentalists, and industry representatives to iron out a process for building a treatment facility - as well as for gaining public trust.

For more than a year, the state Department of Environmental Management (DEM) has provided $100,000 to eight grass-roots organizations throughout Massachusetts that educate people about hazardous waste.

One group here, the Southeast Task Force on Environmental Management, has participated in several activities to bring the issue to the public's attention. ''The Great Waste Debate'' was one.

Two debate participants, an EPA representative and a Harvard professor, discussed the best way to handle hazardous wastes - by treating them on the site where they are produced, or by shipping them to an off-site facility for treatment.

Hugh B. Kaufman, a toxic waste specialist for the Environmental Protection Agency, says 240 million metric tons of hazardous waste are produced each day in the United States. The waste comes from places as diverse as manufacturing industries, oil companies, printers, and dry-cleaners. ''Ninety percent of it is being handeled improperly,'' he says.

Mr. Kaufman says he personally does not favor building large treatment facilities where industries would send their waste, saying such an arrangement allows industries to wash their hands of responsibility for the toxic byproducts they produce. Industries should be compelled to treat their own waste ''in their own backyards,'' he says.

But Michael O'Hare, a professor at Harvard University and former assistant secretary of environmental affairs in Massachusetts, envisions a plan that would include off-site treatment facilities. Because it's expensive to recycle some types of waste, small companies do not have the resources to do it, he says. They need the option of sending the material to a facility specifically designed to treat it. Such a facility offers the best safeguard to improper handling, he says.

However, Dr. O'Hare says, ''there is no one answer to hazardous waste. We need to put together a package'' to encourage industries to reduce the waste they generate to the absolute minimum and treat wastes that can be economically and safely processed by the manufacturers on site.

In addition to ''The Great Waste Debate,'' the Southeast Task Force on Environmental Management has helped organize the following events:

* Several local industries have opened their doors to the public to show how chemicals are being used now. DEM commissioner Jim Gutensohn says plant tours are the best way to show the public that chemicals are being handled properly now.

* For two years the task force has sponsored a course for schoolteachers on environmental issues, at Southeastern Massachusetts University in North Dartmouth.

* Poster and essay contests have been held in Taunton public schools in conjunction with lessons on responsible hazardous-waste disposal.

Commissioner Gutensohn says these coalitions offer the best chance of building a consensus on hazardous-waste issues. The success of the Southeast Task Force shows ''there is hope,'' he says.