In early 2018, residents of Boise, Idaho were told by city officials that a breakthrough technology could transform their hard-to-recycle plastic waste into low-polluting fuel. The program, backed by Dow Inc, one of the world’s biggest plastics producers, was hailed locally as a greener alternative to burying it in the county landfill.

A few months later, residents of Boise and its suburbs began stuffing their yogurt containers, cereal-box liners and other plastic waste into special orange garbage bags, which were then trucked more than 300 miles (483 kilometers) away, across the state line to Salt Lake City, Utah.

The destination was a company called Renewlogy. The startup marketed itself as an “advanced recycling” company capable of handling hard-to-recycle plastics such as plastic bags or takeout containers – stuff most traditional recyclers won’t touch. Renewlogy’s technology, company founder Priyanka Bakaya told local media at the time, would heat plastic in a special oxygen-starved chamber, transforming the trash into diesel fuel.

Within a year, however, that effort ground to a halt. The project’s failure, detailed for the first time by Reuters, shows the enormous obstacles confronting advanced recycling, a set of reprocessing technologies that the plastics industry is touting as an environmental savior – and sees as key to its own continued growth amid mounting global pressure to curb the use of plastic.

Renewlogy’s equipment could not process plastic “films” such as cling wrap, as promised, Boise’s Materials Management Program Manager Peter McCullough told Reuters. The city remains in the recycling program, he said, but its plastic now meets a low-tech end: It’s being trucked to a cement plant northeast of Salt Lake City that burns it for fuel.

Renewlogy said in an emailed response to Reuters’ questions that it could recycle plastic films. The trouble, it said, was that Boise’s waste was contaminated with other garbage at 10 times the level it was told to expect.

Boise spokesperson Colin Hickman said the city was not aware of any statements or assurances made to Renewlogy about specific levels of contamination.

Hefty EnergyBag, as the recycling program in Boise is known, is a collaboration between Dow and U.S. packaging firm Reynolds Consumer Products Inc, maker of the program’s orange garbage sacks and popular household goods such as Hefty trash bags, plastic food wrap and aluminum foil. Hefty EnergyBag said in an emailed response to questions that it “continues to work with companies to help advance technologies that enable other end uses for the collected plastics.” It declined to answer questions about Renewlogy’s operations, as did Dow spokesperson Kyle Bandlow. Reynolds did not respond to requests for comment.

The collapse of Boise’s advanced recycling plan is not an isolated case. In the past two years, Reuters has learned, three separate advanced recycling projects backed by other major companies – in the Netherlands, Indonesia and the United States – have been dropped or indefinitely delayed because they were not commercially viable.

In all, Reuters examined 30 projects by two-dozen advanced recycling companies across three continents and interviewed more than 40 people with direct knowledge of this industry, including plastics industry officials, recycling executives, scientists, policymakers and analysts.

Most of those endeavors are agreements between small advanced recycling firms and big oil and chemicals companies or consumer brands, including ExxonMobil Corp, Royal Dutch Shell Plc and Procter & Gamble Co (P&G). All are still operating on a modest scale or have closed down, and more than half are years behind schedule on previously announced commercial plans, according to the Reuters review. Three advanced recycling companies that have gone public in the last year have seen their stock prices decline since their market debuts.

Full Investigative Report at Reuters.