And though Colorado law allows a plan increase of up to 15 percent for those who use tobacco, he says, there have been no discussions of a similar provision for marijuana, which became legal in the state on Jan. 1.

“The law is very clear on what you can rate on,” Waldron says. “You can rate on tobacco; you can rate on age and geographical area, but you can't rate on other things” — including alcohol and marijuana use.

In Washington, meanwhile, where the first retail marijuana shops opened July 8, insurance insiders say it's too early to tell what effect, if any, the availability of legal pot will have on health insurance.

Kara Klotz, public affairs and social media manager for the Washington State Office of the Insurance Commissioner, notes that “health insurance plans that are regulated by the Washington Insurance Commissioner are very limited in what types of health-related questions they can ask their subscribers, and they are not allowed to charge certain subscribers more than other subscribers” — including those who use alcohol or tobacco.

While legal marijuana is, so far, a nonissue with carriers, medical marijuana — now legal in 20 states, including Colorado — is facing an identity crisis of its own. Still illegal under federal law, medical marijuana is not covered by any health insurance plans, says Susan Pisano, vice president of communications at America's Health Insurance Plans.

“Marijuana is still considered a schedule 1 drug under the controlled substance act,' Pisano says, “which means that, according to their definition, there is no recognized medical use and a high potential for abuse.”

Additionally, Pisano said there continues to be concern about a lack of evidence about the benefits of medical marijuana as well as concern about its potential harm.

Fast Eddy Aki'a smokes a joint as thousands gather to collectively light up at 4:20 p.m. in Civic Center Park in Denver. ©thinkstock.com/Marc Piscotty

One area in which medical marijuana is given at least tacit approval is life insurance.

In an article on LifeHealthPro last year, author Brad Cummins notes that patients need to disclose their medical marijuana use up front or risk being denied, but once that has occurred, “some companies will rate applicants as a standard smoker, giving them double the rates of those as a nonsmoker, while others are okay for occasional use. The rules and ratings vary widely.”

Most carriers charge nonsmoker rates to those who use marijuana occasionally, and a smoker's rate for those who use it more than once a week.

Marijuana may not yet be a concern for insurers, but some doctors believe that pot use eventually will need to be discussed in the same breath as tobacco use. Philadelphia-area physician Bindu Kumar, in a January op-ed in Philadelphia magazine, cited educational campaigns around tobacco use and their effectiveness in stopping kids from smoking.

“I'm not equating tobacco to pot,” she said, “but there are clearly still health issues that can arise.”

Kumar also wrote about the potential risks pot present in the workplace, for example: “an employee shows up to work high on marijuana, with visibly impaired judgment and makes a catastrophic error that leads to harm. Are we OK with this? Of course not — it's no different than alcohol-related incidents,” she said. “However, all this talk about legalizing marijuana has to be balanced with an ongoing discussion about its possible impact on concentration, judgment, memory and reaction time — all of which can be impaired with use.

“We can't just think of the recreational enjoyment,” Kumar said. “Employers need to factor this issue in to their human-resource policies; physicians will need to consider marijuana usage similar to alcohol when assessing their patients; and public-health officials will have to re-brand their tobacco campaigns to include pot.”

– Greg Glasgow