Craig Wedge floors his pickup and the souped-up diesel engine of his Ford F-350 Power Stroke rumbles like a muscle car, blasting black smoke through an unfiltered exhaust pipe.
He and other diesel enthusiasts call this burst of unburned fuel “rolling coal”; for many of them, it is an act of protest against environmental regulations. In defiance of the law, coal rollers disable or discard their trucks’ pollution controls and modify their engines to maximize power and blow smoke with the flip of a switch.
“It might have something to do with being a rebel . . . and trying to prove something to other people,” said Wedge, 37, a computer engineer from Brockton who runs a popular Facebook group called Diesels of New England, which has attracted more than 5,000 members in the past four years.
Some — although not Wedge — have even targeted the owners of hybrid vehicles with their wrath. Hundreds of YouTube videos show coal rollers showering unsuspecting drivers with clouds of what they dub “Prius repellent.” Others park their trucks in spots reserved for hybrids or electric cars.
The movement, if one can call it that, includes regional groups such as Coal Rollers of Massachusetts, Cape Cod Coal Rollers, Maine Coal Rollers, and Connecticut Coal Rollers.
“Who does the EPA think they are to tell us what we can and can’t do with our vehicles?” Wedge said.
The Environmental Protection Agency and advocates say diesel vehicles contribute to global warming and exacerbate health problems. Their emissions are known to cause cancer and have been linked to premature deaths from heart and lung disease.
“Just because you don’t like the laws, it’s not your right to break them without punishment,” said Conrad Schneider, a spokesman for the Clean Air Task Force, a Boston-based environmental advocacy group. “It’s like someone walks into a public place where smoking is prohibited and lights a cigar.”
But Wedge and others grumble that the government has gone too far in its crackdown on diesel vehicles, which they revere because their engines last longer and offer greater fuel efficiency and torque than conventional gas engines.
Many of them air their gripes on pro-diesel Facebook pages, where they joke about how climate change is a hoax or overblown and voice a litany of grievances against the government, especially the EPA.
Among their complaints: the ultra-low sulfur diesel fuel mandated by the federal government costs significantly more at the pump and corrodes older trucks’ expensive fuel injectors; particulate filters required on new vehicles sap about 30 percent of their fuel efficiency; and other rules about air flow and special injections lead to premature engine failure.
EPA officials and environmental advocates say the regulations are vital to reducing the amount of soot and carbon dioxide emitted by the nation’s estimated 11 million diesel vehicles — including about 200,000 in Massachusetts.
Despite the raft of regulations, which include requirements that take effect this year to increase the fuel efficiency of pickups and big rigs, resilient diesel engines mean many older vehicles that lack particulate filters and other emissions devices will remain on the road for decades to come. Widespread tampering with emissions controls on newer diesels could blunt EPA projections that their regulations will prevent at least 39,000 premature deaths and save about $300 billion in public health costs by 2030.
“We will consider any appropriate enforcement actions based on the specific aspects of the cases,” said Enesta Jones, a spokeswoman for the EPA.
Environmental advocates say they are not laughing at the proliferation of coal rolling videos online. In a 2005 study, the Clean Air Task Force, which organized the national clean diesel campaign, estimated diesel leads to 27,000 heart attacks and 400,000 asthma attacks each year and shortens the lives of an estimated 21,000 people a year in the United States.
Even a small number of diesel vehicles on the road with dismantled particulate filters can have a significant health impact, said Jon Levy, a professor of environmental health at the Boston University School of Public Health.
“This backlash means more particulate matter, and that means more heart attacks and asthma attacks,” he said.
Evidence of the impact of filters comes from a study released this month by the Northeast States for Coordinated Air Use Management, which found that the amount of soot in the air in Dudley Square in Boston dropped by more than half after the MBTA and Boston Public Schools installed diesel particulate filters on their buses a decade ago.
Some diesel enthusiasts, however, say the older trucks are better for the environment than many of the newer vehicles, even those powered by gas or hybrid engines.
“It’s an oxymoron,” said Sarah Meaney, 24, of Palmer, who owns two pickup trucks, including a 1999 Ford F-350 Super Duty that has logged 335,000 miles. “They’re now making the trucks less fuel efficient with engines that last half as long. So you’re wasting more engines and more parts, and all the energy and fuel that goes into building the new trucks is wasted.”
Many diesel enthusiasts insist their tinkering is more a hobby than political protest. They acknowledge they are breaking the law — though most manage to pass emissions inspections because their modifications are mainly internal and the amount of smoke from their exhausts can be controlled by dashboard computers — but they wish the government would just leave them alone.
“This is about freedom,” said Fred Johnson, 32, who owns Diesel Shop in Jewett City, Conn.
He said it has become much harder in the past year to stock his shelves with exhaust systems that lack filters and handheld programming devices that make it easy to switch off emissions controls. The companies that used to sell these after-market parts have stopped because of government pressure.
“I lose a lot of business, because people want to roll coal,” he said, adding he will only modify trucks that engage in competition.
For Craig Wedge, speed and strength are key parts of the lure of diesels, which he calls “the backbone of the country.”
On a recent morning near his office in Canton, he showed off the modifications he has made to his 2009 Ford, which he has primped with blue flame decals and buffed tires. They include a free-flowing exhaust, a cold air intake system, and a dashboard computer that allows him to tweak his engine’s performance. The diesel particulate filter and catalytic converter also have been removed.
Wedge boasts he can get up to 20 miles per gallon on the highway — as much as 6 miles per gallon better than when he bought the truck, which is still going strong with 120,000 miles on the odometer.
Then he demonstrated how easy it is to roll coal, which he said he does only rarely, especially given that it costs about $125 to fill his tank. After a few clicks on the computer, he revved the engine, the oversized tires shrieked, and the black smoke streamed out of the stainless steel exhaust pipe.
He raced up and down the street, the dense cloud of smoke drifting high into the air with the white smoke from his spinning tires. When he finally pulled back into the parking lot by his office, he smiled.
“It’s fun,” he said.