Updated

Marijuana-related calls to poison control centers in Washington and Colorado have spiked since the states began allowing legal sales last year, with an especially troubling increase in calls concerning young children.

But it's not clear how much of the increase might be related to more people using marijuana, as opposed to people feeling more comfortable to report their problems now that the drug is legal for adults over 21.

New year-end data being presented to Colorado's Legislature next week show that the Rocky Mountain Poison and Drug Center received 151 calls for marijuana exposure last year, the first year of retail recreational pot sales. That was up from 88 calls in 2013 and 61 in 2012, the year voters legalized pot.

Calls to the Washington Poison Center for marijuana exposures jumped by more than half, from 158 in 2013 to 246 last year.

Public health experts say they are especially concerned about children accidentally eating marijuana edibles. Calls involving children nearly doubled in both states: to 48 in Washington involving children 12 or under, and to 45 in Colorado involving children 8 or under.

"There's a bit of a relaxed attitude that this is safe because it's a natural plant, or derived from a natural plant," Dr. Alex Garrard, clinical managing director of the Washington Poison Center. "But this is still a drug. You wouldn't leave Oxycontin lying around on a countertop with kids around, or at least you shouldn't."

Around half of Washington's calls last year resulted in hospital visits, with most of the patients being evaluated and released from an emergency room, Garrard said. Ten people were admitted to intensive care units — half of them under 20 years old.

Children who wind up going to the hospital for marijuana exposure can find themselves subject to blood tests or spinal taps, Garrard said, because if they seem lethargic and parents don't realize they got into marijuana, doctors might first check for meningitis or other serious conditions.

Pot-related calls to Washington's poison center began rising steadily several years ago as medical marijuana dispensaries started proliferating in the state. In 2006, there were just 47 calls. That rose to 150 in 2010 and 162 before actually dropping by a few calls in 2013, a year in which adults could use marijuana but before legal recreational sales had started.

Calls about exposure to marijuana combined with other drugs spiked in Colorado, too. There were 70 such calls last year, up from 39 calls in 2013 and 49 calls in 2012.

Both states saw increases in calls across all age groups. Colorado's biggest increase was among adults over 25 — from 40 in 2013 to 102 calls last year. Washington had a big jump in calls concerning teens, from 40 in 2013 to 61 last year.

Many of the products involved in Washington's exposure cases are found at the state's unregulated medical marijuana dispensaries, but not licensed recreational shops, which are barred from selling marijuana gummy bears or other items that might appeal to children, Garrard said.

The Washington Legislature is working now on proposals for reining in the medical marijuana industry — and limiting what they can sell. Both states have taken steps to try to keep marijuana products away from children, such as requiring child-resistant packaging in licensed stores.

In Denver, authorities charged a couple with child abuse last month, saying their 3-year-old daughter tested positive for marijuana. The couple brought the girl to a hospital after she became sick.

Ben Reagan, a medical marijuana advocate with The Center for Palliative Care in Seattle, said at a recent conference that he had long dealt with parents whose children accidentally got into marijuana. It used to be less likely that they would call an official entity for help, he said.

"Those things have been occurring this whole time," Reagan said. "What you now have is an atmosphere where people are much more comfortable going to the emergency room."

"Before, you'd just look at your buddy and say, 'Sorry, dude. You're going to have to deal with it all night,' " he added. "'We're not calling nobody.'"