MINNEAPOLIS — A federal prosecutor told jurors Tuesday that a Duluth head shop owner illegally sold synthetic drugs, making tens of thousands of dollars a day, while defense attorneys countered that the substances were not banned.

Jurors heard opening statements in the trial of Last Place on Earth owner Jim Carlson. Carlson, his girlfriend and his son are charged in a 55-count indictment with illegally selling banned synthetic drugs by allegedly “misbranding” them as herbal incense, bath salts and other names.

In his opening statement, Assistant U.S. Attorney Surya Saxena accused the three of conspiring to circumvent federal statutes.

“They are recreational drugs used to get high,” Saxena said. “They called the product one thing when they were something else.”

Defense attorney Randall Tigue countered that the chemical compounds the head shop sold were not banned and that Carlson obeyed the law.

“If a drug was banned, he would not sell it,” Tigue said. “He did it from Day One and he did until the day it (the store) closed.”

Carlson’s downtown store is currently shuttered pending the outcome of a nuisance suit brought by the city of Duluth.

On video monitors in front of the jurors, Saxena showed them a photo of a line of people waiting to get into Carlson’s store.

He said Carlson labeled the drugs not for human consumption though they clearly had one purpose, which Saxena said was to be ingested, snorted or inhaled. He said Carlson asked his employees to try out the compounds to let him know the effects.

Saxena promised to show jurors an email that he said Carlson sent in which he acknowledged selling the drugs was a risk but said he was making so much money he was going to continue to sell them. Sexena said there would be evidence that store raked in tens of thousands of dollars a day and made millions.

The trial is expected to last two to three weeks.