They might be the only businesses in Colorado begging for their products to be taxed.

But a number of medical-marijuana dispensaries say taxation is critical for their industry’s long-term health, and many say they’ve been collecting sales taxes for months — before a legal opinion issued Monday saying their products are taxable.

After the opinion from Attorney General John Suthers, medical-marijuana dispensaries could be facing penalties for not collecting sales taxes that could include fines and, ultimately, seizure.

Mark Couch, a spokesman for the Colorado Department of Revenue, said agency officials met Monday to discuss sending a letter to dispensaries statewide to inform them about paying the state’s 2.9 percent sales tax.

“We’ll be actively contacting them to remind them of their legal obligations,” Couch said.

Dispensaries also must obtain state retail sales-tax licenses, which cost $4 for one year. Starting in January, businesses can purchase two-year licenses for $16.

Suthers’ opinion said medical marijuana is subject to state sales tax as are food products made with it. Marijuana seed, however, is considered an agricultural product and exempt from sales tax.

For dispensary owners like Miles Zalkin, who operates Pain Management of Colorado in Denver, the opinion just means business as usual.

“We’ve been collecting sales tax from Day One,” said Zalkin, whose business has been open just over a year. “We run our business as if it was regulated.”

Zalkin estimated he’s collected tens of thousands of dollars in Denver and state sales taxes.

“We are in favor of taxation,” he said. “We are in favor of seeing new regulation come in and clean this industry up.”

Couch said that of some 60 dispensaries in Colorado that revenue officials have identified — and he said there may well be more — about half are paying sales taxes.

He said the department has no way to track how much has been collected in sales taxes from dispensaries, and the agency has no estimates of how much revenue medical marijuana will generate.

California officials reported having collected about $11.4 million in tax on some $142 million of medical-marijuana sales in 2005-06.

A number of cities and counties have taken the position that sales taxes apply to medical marijuana. Boulder officials estimated the city is reaping between $2,400 and $3,000 a month from medical-marijuana sales.

City officials in Denver said the city has no estimate on how much sales-tax revenue the dispensaries will produce but is preparing to instruct dispensaries on how to collect the sales tax and remit it to the city.

Denver’s sales tax is 3.62 percent.

Ernie Travis, owner of Boulder Vital Herb, said he recognized early that paying sales taxes was important “to make marijuana look legitimate to the community.”

Travis added, “There’s a lot of positive things marijuana can do. Taxes is just one of them.”

Lawmakers likely will be asked in January to set up regulations on the industry. For Rep. Steve King, a Grand Junction Republican and a veteran police officer who used to present anti-drug programs in schools, the irony is inescapable.

“It is absolutely weird,” King said about the thought of regulating the sale of marijuana, “but just because I may not like a law doesn’t mean I don’t have an obligation to make it so it’s functional.”

Tim Hoover: 303-954-1626 or thoover@denverpost.com