Pot brownie meet the Cannabis Car. A Key West, Fla., man has come become the latest, though not the first, to extol another wonder of the miracle plant: a car mostly made of hemp that he says can cut the carbon footprint of the planet’s estimated 1 billion cars and cover much-needed ground in the fight against climate change.

But a warning: you can’t smoke this car.

“Theoretically, you can smoke anything you want to, but it would not be good idea,” said Bruce Dietzen, president of Renew Sports Cars, who says he regularly gets asked if he smokes marijuana.

For the record, he does not. And also for the record, the car is made of hemp, a less potent cousin of marijuana that for thousands of years has been used to make rope and now a fiberglass-like plastic.

Dietzen, a retired Dell computer salesman, completed the car in his garage last year after moving to the island 16 years ago with a mini fleet of sports cars, mostly curvy Italian and British classics from the 50s that served as his models. Using the chassis of a Mazda, Dietzen built the zippy red Cannabis Car from about 100 pounds of imported Chinese hemp. Woody material from inside the hemp stalk is combined with a resin to form a kind of super-strong plastic that is then molded into a car body.

Dietzen says he will take custom orders for the cars — prices range from $40,000 for a 130-horsepower model and go as high as $197,000 for a 2,300-pound edition powered by a fire-breathing 640-horse engine. But he stresses he is less interested in finding the next big eco car company than providing inspiration for existing ones.

“All I want to do is build one car at a time, one day at a time,” said Dietzen, who in September drove to Chicago to show off the car at Willie Nelson’s 30th annual Farm Aid benefit concert.

“I’m 61. I’m not gong to go out there and get a bunch of people for financing who want to make quarterly numbers because that’s a good way to sink a company. I’m doing it out of my belief in what needs to be done,” he said. “I didn’t want to look at the end of my career and say, ‘Wow, I sold a bunch of computers.’ ”

Dietzen believes his car may be the only hemp car now in production, though by no means the first.

In 1941, Henry Ford unveiled the Soybean Car. But production was derailed when World War II broke out. Exact ingredients aren’t known, though Ford historians believe the car was constructed of hemp, wheat straw and flax held together by a soybean-based resin.

“It’s not that he cared about the environment but because he was raised on a farm, he loved farmers and the farmers back then were in as bad a shape as they are today,” Deitzen said.

What intrigued Deitzen was the flexibility of using cannabis-based hemp, and its strength. Nearly every piece of his car that could be made of hemp is, including the body, dash and rugs. Engine parts, the car frame, windshield switches and other mechanical and electrical parts are not. Manufacturing a car from cannabis, and fueling it with biofuels, could have huge carbon rewards, he said.

“You have a car operating in a carbon negative environment,” he said.