DULUTH — The face of synthetic drugs in Minnesota belongs to a man who looks like an aging rocker, says he talks too much and describes his struggle to do what’s right as a battle between his inner Yoda and Darth Vader.

Jim Carlson is also a businessman — one who has grown wealthy by operating in what he called a “gray area” of synthetics, which he claims are legal, despite objections by police.

“I am just a firm believer that people should be able to do what they want,” he said. “It’s not strictly a monetary thing with me. If somebody wants to buy this product they should have a right to, if they are not harming other people.”

Carlson isn’t the only seller of synthetics in Minnesota, but his skirmishes with the city of Duluth and his outspoken nature — he says he’s called “The Mouth” in the industry — have thrust him to the fore of what officials view as a new threat to public health. On Sept. 21, police raided Last Place on Earth, his colorful shop a few blocks from the shore of Lake Superior, and carted away $50,000 in herbal incense, several guns and Carlson’s son, who was working as a clerk.

But 24 hours later, Carlson had more incense, also called synthetic marijuana, in stock — and customers were once again lining up.

He insists his incense doesn’t contain substances banned by federal or state authorities, so he’s doing nothing wrong. But police say the incense is illegal because Minnesota law also bans lookalikes of those substances, or anything that gives a similar “stimulant, depressant, or hallucinogenic effect.”

“I’m not sitting there daring the police to come and get me,” he told The Associated Press just hours before his shop was searched. “I wish they’d leave me alone to tell you the truth, but if they do come and get me, I will fight them.”

Still, Carlson acknowledges he’s in a “gray area.” He is challenging the Minnesota law, which took effect July 1. Until the courts sort it out, he says, he’ll keep selling incense — even if it means more police searches. He said others in the industry are watching his lead.

“It’s unfortunate if he is continuing to sell those products,” said Duluth police Lt. Steve Stracek. “We aren’t going away until the problem goes away.”

Data from the American Association of Poison Control Centers shows an alarming increase in the number of people reporting exposure to synthetic drugs. Through August, centers nationwide received 4,720 calls about synthetics marketed as bath salts so far this year — compared with 303 calls during all of 2010. For synthetic marijuana, the centers received 4,421 calls as of the end of August, compared with 2,915 last year.

Synthetics have been linked to deaths around the country, including two in Minnesota: a teenager in Blaine overdosed on a party drug in March and a young man who shot himself in Maple Grove after smoking synthetic pot in April, though his parents have said the drug wasn’t a factor.

Carlson says cigarettes and alcohol cause more deaths — including his own brother’s, who died from drinking. But those products are legal because people want them, he said, and the same should apply to synthetics. He’d actually prefer to sell marijuana, and hopes synthetics are a step toward legalizing it.

In the past 30 years, Last Place on Earth has sold everything from tobacco and pipes to sex toys and urine cleansers. About two years ago, Carlson started selling herbal incense and was amazed at its popularity; his first shipment sold out in a couple hours.

These days, the incense is big business — accounting for 95 percent of sales. On his busiest days, he sells about $16,000 in incense alone. He’s made enough over the years to buy multiple properties — including a vacation home in Mexico.

Carlson, 54, has been around the vice business since birth. He claims his father owned the first head shop in Minnesota in the 1960s, and was arrested for selling pornography back then. As times changed, Carlson also fell under law enforcement scrutiny — his pipes were seized, and returned, in the 1980s and he’s fought authorities over his nitrous oxide and other products. He has no convictions on record.

Yet he acknowledges his business is one of legal loopholes and he tries to stay a step ahead. He says his incense is not for human consumption, but knows his customers use it like pot — so he won’t sell to kids. “We try to be responsible,” he says. He legally can’t sell marijuana pipes, so his pipes are for tobacco. He doesn’t sell banned clove cigarettes, but offers clove cigars.

Experts warn that just because a drug is in a store, it may not be OK. Synthetic marijuana has led to seizures. And bath salts — more like methamphetamines or cocaine — can cause heart problems or kidney failure, said Dr. Jon Cole, an emergency room physician at Hennepin County Medical Center and the medical director for the Minnesota Poison Control System.

“These substances are dangerous and people should not be using them and believe that they are safe,” he said.

Carlson counters that anything done to excess or used the wrong way can be harmful. He cited himself as an example, noting he once weighed 380 pounds from overeating, before stomach surgery.

“So nobody should be able to have a doughnut because I don’t have any control over it and it was killing me?” he said. “Where does the government draw a line?”

Carlson began selling bath salts a year ago but stopped in mid-September, despite his beliefs that they are legal.

“The government doesn’t like the incense, but they really hate the bath salts,” he said. “We felt we could ride longer with the incense and fight this stronger rather than doing both of them.”

After police raided him anyway, he was tempted to resume bath salt sales, but hasn’t.

“It’s like I have two people inside of me. One is Yoda and one is Darth Vader, and Yoda is telling me, ‘Stay away from the dark side, don’t sell bath salts,’ but Darth Vader is telling me, ‘They are doing this to harass you, pull in the bath salts,”’ he said.

But bath salts or not, business is good.

On a recent weekday, 25 people lined up in the rain half an hour before the store opened. Some were just buying tobacco, but many were seeking incense. While on this day, most of the customers were locals, Carlson says he gets patrons from as far as southern Minnesota, the Dakotas and Michigan.

Some refer to him affectionately as “Pops” or “Jimmy,” while others say they like knowing they can ask about a product if they have a question. Some customers say if it weren’t for Carlson’s store, they’d be buying marijuana illegally off the street.

Sabrina Endres, 26, of Duluth, was waiting to buy No Name incense for herself and her father, who she said is in hospice with lung cancer. The incense helps his appetite, she said, and she smokes it a couple times a day to calm her hyperactive disorder.

“I like smoking it better than I do weed,” she said. “With this, I know what I’m getting myself into versus marijuana. With marijuana, you don’t know — it could be laced with anything.” She said someday she hopes her kids go to Carlson’s store: “I’d rather my kids come here than go to some dirty house around the corner looking for drugs.”

Half an hour up the road from Duluth, Lynn Habhegger has a very different view. Her son was 24 when he landed in intensive care this summer after suffering a heart attack and renal failure from mixing bath salts with a drink, she said. She wants synthetics off the street.

“To me this is a moneymaking machine,” she said of Carlson. “In my opinion he’s a drug pusher.”