By Kathy Walsh

AURORA, Colo. (CBS4) – More Colorado children are ending up in the emergency room because of legalized marijuana. A new study by Colorado researchers and published online by JAMA Pediatrics found emergency department visits and regional poison center calls increased after pot was available for recreational use.

The average rate of marijuana-related visits to the children’s hospital increased from 1.2 per 100,000 population two years prior to legalization to 2.3 per 100,000 population two years after legalization.

Annual RPC (regional poison center) pediatric marijuana cases increased more than five-fold from nine in 2009 to 47 in 2015.

Colorado saw an average 34 percent increase in RPC cases per year compared with a 19 percent increase in the rest of the United States.

Sources of marijuana were a parent, grandparent, neighbor, friend, babysitter or other family member.

According to the study, more than half of the children taken to the hospital ingested the drug in edible forms such as candy and baked goods.

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“Something that looks and tastes just like a non-infused product … your child is obviously going to eat and be unaware,” said Dr. G. Sam Wang at the University of Colorado Anschutz Medical Campus and lead author of the study.

Wang told CBS4 Health Specialist Kathy Walsh that Children’s Hospital Colorado has seen the trend.

“In 2009, we saw one child here with a marijuana exposure that we know of in the emergency department. And in 2015, we saw 16,” said Wang.

He said, with pot more available, researchers expected more young children would be exposed. But a five-fold increase in calls to a regional poison center was dramatic.

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Wang said often the products weren’t in child-resistant packages, there was poor supervision or product storage issues.

He said some kids had minimal symptoms like sleepiness. Others had difficulty breathing.

“We had a couple children who needed a ventilator to help them breathe until the effects wore off,” said Wang.

Researchers concluded as more states pass laws legalizing recreational marijuana, more effective measures are needed to keep it out of the pediatrics population.

Kathy Walsh is CBS4’s Weekend Anchor and Health Specialist. She has been with CBS4 for more than 30 years. She is always open to story ideas. Follow Kathy on Twitter @WalshCBS4.