And yet, companies are selling vehicles with a similarly fatal flaw. The Tennessee-based manufacturer Fitzgerald Glider Kits, for instance, is in the business of buying up wrecked or otherwise not roadworthy old 18-wheelers, rebuilding the outdated engines and other drive train components, and then installing them in brand new vehicle bodies, or “gliders,” as vehicles without powertrains are called. Fitzgerald and other smaller manufacturers like Phoenix Inc. in Indiana and Harrison Truck Centers of Iowa have already ramped up from 1,000 to 10,000 kits a year since 2010 and are likely to grow.

Fitzgerald’s business model is primarily designed to circumvent Environmental Protection Agency regulations on diesel emissions. They explicitly advertise using rebuilt diesel engines that pre-date the first, major diesel emission standards that went into effect in 2007 and thus don’t have to meet modern standards. If old engines are rebuilt following original specifications, the engines are technically legal. A 2005 truck with a rebuilt engine is a 2005 truck. But when the 2005 engine is now installed into a 2017 “glider” kit and masquerades as a 2017 truck, cannibalizing 2017 truck sales, and does it with a cost advantage, that is not an even playing field.

Not only does driving a truck with outdated equipment put the driver and surrounding motorists at risk, the truck’s emissions cause a range of serious illnesses, lung cancer, and even death. Terminal lung cancer or flying through the windshield—both have the same result. The difference is that the EPA is proposing to allow more of these deadly retrofitted trucks. On Nov. 9, just weeks after EPA Administrator Scott Pruitt had a one-on-one meeting with Fitzgerald, and ignoring the huge health risks documented by his own engineers, he proposed to roll back the regulations. He claims that the EPA is overreaching its authority.

Part of the problem may be that, from the outside, the brand new “glider kit” trucks built on bodies purchased by Fitzgerald from Peterbilt, Freightliner, Volvo, or Navistar would fool even the veteran trucker. Because they use refurbished engines, the glider-kit trucks can also be as much as 25% cheaper than modern trucks. But inside, these trucks emit pollution 43 to 55 times the level of a 2014 and 2015 model year, according to studies conducted by the EPA.

I served as the director of the Office of Transportation and Air Quality at the U.S. EPA and, beginning in 2000, under President Clinton, we implemented a set of historic regulations to nearly zero-out the toxic pollution from diesel engines, starting with the 2007 model year engines. These measures helped prevent 8,300 premature deaths and hundreds of thousands of respiratory illnesses. Today, a 2017 model year diesel truck or bus sold in the U.S. is over 98% cleaner than one 17 years ago. And, these new clean diesel engines deliver 3% to 4% fuel savings for each truck.

These innocuous-sounding “glider kits” account for only 5% of the trucks on the road today but are growing in numbers and are likely to emit one third of all soot and NOX pollution from long-haul trucks by 2025. That translates to as much as 1,600 premature deaths, according to the EPA’s own testing. The glider kits spew so much pollution, that in one year, their emissions will be 13 times more than what VW‘s emissions cheating vehicles would have spewed by 2025.

Earlier this month, the EPA held a public hearing on this life-and-death matter. Testifying against the proposal were states, environmental and health groups, and virtually every major truck and engine manufacturer. These companies have invested heavily in creating the much cleaner vehicles that are on the road today. Susan Alt, senior vice president of public affairs for Volvo Group North America, said the EPA’s proposal “makes a mockery” of the company’s investments to develop clean diesel engines and will “hurt a large number of small businesses who are not selling glider vehicles.”

A decision that rewards a group of companies that manufacture roughly 5% of the trucks on the road today is astounding—even given president Trump’s and administrator Pruitt’s antipathy toward environmental regulations. Some experts have suggested that the decision to allow unlimited numbers of glider kits to be sold, which will cost thousands of American lives, is just political payback. In August 2016, Fitzgerald hosted candidate Trump at a campaign event in its Tennessee facilities.

Rolling back progress on standards that saves lives makes no sense. We know unregulated emissions kill people. Most manufacturers have bought into a workable solution and that has created a level, competitive playing field for those that invested. And, yet, the EPA is proposing that we allow unlimited numbers of the dirty, old engines back on the roads.

It’s really no different from allowing manufacturers to sell cars without seatbelts. So, let’s demand “seatbelts” that protect our future as we are in for a ride—a ride for our lives.

Margo Oge, who served as the director of the EPA’s Office of Transportation and Air Quality from 1994 to 2012, is the author of Driving the Future: Combating Climate Change with Cleaner, Smarter Cars.