Companies whose futures depend on plastic production, including oil and gas giant ExxonMobil, are trying to persuade the federal government to allow them to put the label “recyclable” on bags and other plastic items virtually guaranteed to end up in landfills and incinerators.

They argue that “recyclable” should apply to anything that’s capable of being recycled. And they point to newer technologies that have been able to remake plastic bags into new products.

I spent months investigating one of those technologies, a form of chemical recycling called pyrolysis, only to find that it is largely a mirage. It’s inefficient, dirty and so limited in capacity that no one expects it to process meaningful amounts of plastic waste any time soon.