FLINT (Michigan)•Mammoth bins and barrels line the edge of a General Motors (GM) factory floor, stuffed with industrial detritus like shavings of aluminium, pieces of plastic and glass and chemical sludge that has come off the machines that are used to assemble engines for three models of Chevrolet. Every bit of it, GM promises, has a future.

It has been more than 12 years since this plant in Central Michigan has sent anything to a dump. The 733,000 sq ft Flint Engine facility was GM's first to achieve what is known as zero-waste to landfill - a designation now held by more than 150 of its factories and office buildings worldwide.

Not only is GM trying to avoid sending waste to landfills, it is also trying to intercept other would-be garbage. Mr John Bradburn, GM's global waste reduction manager, showed off air filters and noise-damping insulation for the Chevrolet Equinox engine that had been made from some of the millions of plastic water bottles from the Flint water contamination crisis.

The company also converted 365km of oil-absorbing boom used in the Gulf of Mexico after the Deepwater Horizon explosion in 2010 into air deflectors for the engines of the Chevrolet Volt. GM realises US$1 billion (S$1.3 billion) in revenue each year from the sale of recyclable materials, said Mr Bradburn.

GM is not the only carmaker for which environmental considerations extend beyond what their cars release into the air to what they put into the ground.

Ford has 82 zero-waste facilities worldwide, including the century-old Rouge Center complex in Dearborn, Michigan, which includes six factories and a steel foundry. Toyota, which has 27 zero-waste facilities in North America, said it reused or recycled 96 per cent of its unregulated waste. Fiat Chrysler, Honda, Subaru and others also boast of their waste-reduction efforts to shareholders, customers and the general public.

"The auto industry has definitely been in the lead, paving the way for zero waste for heavy manufacturing," said Mr Gary Liss, the first president of the US Zero Waste Business Council and a board member of the Zero Waste International Alliance.

Part of the reason is, of course, economic. In the 1990s, carmakers manufacturing parts and assembling vehicles in Europe and Asia faced new regulations and increasing costs as landfill space became scarce.

By the early 2000s, car companies operating in North America, where sending waste to landfills has long been cheap because space is plentiful, realised that reducing waste through recycling and reuse yields considerable cost savings as well as positive public relations, said Mr Andy Hobbs, Ford's director of environmental quality.

"This is not just good environmentally and good for our communities, it's also great for shareholders because we pay less to dispose of waste, we reduce our liabilities going forward and we're not putting stuff in a hole in the ground," said Mr Hobbs. He said Ford now sends 3.9kg of waste per vehicle to landfills worldwide, compared to about 39kg in 2007.

Less waste and less expensive means of disposal help keep costs down. "That enables our marketing team and dealers to lower the price of the car," he said.

Mr Bradburn said he expected there would be a significant push in the United States to find ways to recycle and reuse materials closer to home because China began severely restricting foreign companies' abilities to send refuse there in September.

The Chinese government said hazardous waste mixed in with the recyclable material was causing environmental problems. Operation Green Fence, as China has called it, bans the import of 24 varieties of solid waste, including certain plastics and unsorted paper.

"China doesn't want our crap anymore," said Mr Liss, the business council president. "In five or 10 years, China may not want any of our materials. They're saying, 'We don't want your trash. We only want good quality recyclables.' And they generate a lot of their own."

But Mr Bradburn was optimistic about the potential benefits. "This will create economic opportunities to develop jobs and to process materials close to home to reduce energy and carbon footprint," he said. "I see that developing in a significant way into 2018."

The zero-waste push has given rise to dozens of small businesses focused on various minute aspects of the production chain.

Mr Peter Feamster, owner of Innovo, has repurposed plastic in parts containers for carmakers including GM and Ford, and has tried to persuade companies to let him fix up and resell car headlamps that are damaged during assembly. Many of those parts end up in a landfill, Mr Feamster said, but do not count against a corporation's zero-waste data because they are first sent to a third party for recycling.

He said carmakers or suppliers sometimes use original material when recycled material would do just as well because the official specifications demand it.

"I've got customers making parts that go underneath the body of the car, you hardly see it, but the specs say it must be 100 per cent virgin material," Mr Feamster said. "Why would a spare tire cover have to be 100 per cent virgin? Because maybe a customer will say, 'You're using what? Recycled material on my car I just spent $40,000 for?' But I think that's changing."

Mr Kevin Butt, Toyota's North America environmental sustainability director, said carmakers had noticed that the change had already arrived. His company announced in April that part of its US$1.33 billion investment in the Georgetown, Kentucky, plant where the Camry is assembled would include a new paint shop that will eliminate a currently unrecyclable hazardous waste by-product of preparing aluminium for painting.

"There's data out there that more and more people are coming to the conclusion that how we build cars is extremely important to them," he said.

NYTIMES