Forty years ago, the state confronted an environmental crisis tied to garbage disposal.

For generations, most Connecticut towns had disposed of their trash within their own borders, using landfills. As the 1980s arrived, many dumps had reached capacity and often exceeded it, with trash mountains rising over the landscape as the garbage piled higher.

Environmentally, it was a terrible way to deal with waste. Contaminants leaching from landfills threatened surrounding waterways and drinking supplies. Much of the material, such as plastics and glass, would not break down and instead dissolve back into the earth for thousands of years.

The decomposition that did take place released methane, a greenhouse gas about 30 times more potent in trapping heat in the atmosphere than carbon dioxide.

But the state came up with a plan, and a good one. A series of waste-to-energy incinerators were constructed. The privately built and owned plants were managed by local authorities. The garbage became a fuel to create electricity. Since garbage is not an efficient fuel, utilities were obligated by law to pay more for it, the cost passed along to consumers.

Combined with an increase in recycling, it was a major change in the way the state handled trash and the landfills were closed and capped. There are trash-to-energy incinerators in Hartford, Bristol, Bridgeport, Wallingford, Preston and Lisbon.

In Preston, despite local opposition, the trash-to-energy plant opened in the late 1980s to handle the region’s garbage. It did that job until this year, when the local trash-management authority began operating under a new contract with Wheelabrator to take the waste to its plant in Lisbon. But there is more than enough waste to be disposed of, so that Covanta plant in Preston keeps operating at capacity.

This approach was never intended to be the final answer. Plants don’t operate forever. State environmental planners envisioned far more aggressive recycling to greatly reduce the waste stream in the decades to come, and perhaps a next generation of plants to better process what remained.

It hasn’t happened and now Connecticut is slipping backwards.

The state’s largest trash-to-energy plant in Hartford, which handles about 700,000 tons each year, about one-third of Connecticut’s waste, is scheduled to close next June. It would cost $300 million to modernize the plant, which has frequent operational problems. There is no support among state officials to make that investment.

It is not like Connecticut did not see this coming. It has been apparent for years that the Hartford plant’s days were numbered. But no serious effort was made to find a new location and build a new plant, which would have assuredly faced strong opposition.

When it closes, the waste will be trucked to out-of-state landfills, at increased cost. While these may be better engineered than Connecticut’s old landfills — or maybe not — it remains an environmentally poor way to handle garbage.

Other plants will eventually close. Connecticut needs a new plan. A 2015 study concluded the waste stream could be cut 35% by removing compostable materials and using them to produce fuel at anaerobic digestion facilities.

Trash is a dirty problem. Solutions can politically and literally stink. But trucking our problem to other states is a cop out. We can do better.

Paul Choiniere is the editorial page editor.