The public has until Jan. 18 to submit comments on the proposal.

The state is inching closer to mandatory third-party testing of medical marijuana.

This month, the state Department of Health posted proposed regulations outlining the licensing standards for companies that would be responsible for testing the drug for pesticides, metals, solvents and potency.

The public has until Jan. 18 to submit comments on the proposal, which sets the annual licensing fee at $5,000.

The labs, which would require local zoning approval, would be responsible for testing the marijuana produced by the state's 20 licensed cultivators and three dispensaries. Currently, dispensaries conduct internal testing, but the state wants to move to a third-party system that would provide additional checks and balances.

The proposed regulations ban laboratories and their owners from having any "material financial interest or control" in a Rhode Island dispensary or cultivator.

Such rules would prevent a conflict of interest between growers and testers "which could lead to inaccurate testing by personnel ... or misrepresentation of the content of medical marijuana by those parties who stand to gain from selling less potent products at a higher price," the health department wrote.

Earlier this month, the state's top medical marijuana regulator, Norman Birenbaum, told state lawmakers at a hearing that he doesn't expect testing to dramatically increase the price of medical marijuana as the testing cost should be no more than $200 for a 10-pound batch. Competition in the testing market should keep prices low, he said.

Comments can be submitted to Paula Pullano, Rhode Island Department of Health, 3 Capitol Hill, Providence, RI 02908, or to paula.pullano@health.ri.gov.