More children under 6 across the U.S. are being exposed to marijuana, according to a study released on Monday.

The study, conducted by researchers at Nationwide Children’s Hospital and published in the journal Clinical Pediatrics, showed a 147.5% increase in marijuana exposure among children younger than 6 years old between 2006 and 2013. That rate spiked by 610% over the same period in states where marijuana was legalized for medicinal purposes before 2000.

Although the total number of reported cases — 1,969 children between 2000 and 2013 — is not large, the researchers say the rapid escalation in the rate of exposure is a cause for concern. More than 75% of the children who were exposed to marijuana were under 3 years old. They ingested it in the form brownies, cookies and other foods containing the drug.

“Any state considering marijuana legalization needs to include child protection in its laws from the very beginning,” Gary Smith, senior author of the study and director of the Center for Injury Research and Policy at Nationwide Children’s, told Science Daily.

His co-author Henry Spiller says the high instances of marijuana ingestion are most likely due to the popularity of marijuana-laced food.

“Very young children explore their environments by putting items in their mouths, and foods such as brownies and cookies are attractive,” he said.

[Science Daily]

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