AUGUSTA, Maine — A call from an employee of one of the state’s medical marijuana dispensary operations sparked an investigation that found pesticides were being used in violation of rules governing cultivation of the plants, according to a state official.

An employee of Wellness Connection of Maine called the state earlier this month to say pesticides were being used on plants cultivated at the group’s Auburn facility, and investigators found pesticides and more than 20 other violations of rules governing medicinal marijuana.

The state’s medical marijuana rules ban the use of pesticides. Kenneth Albert, Division of Licensing and Regulatory Services director, said the state shared the results of the investigation with Wellness Connection officials on Monday who agreed to stop using pesticides and to make several changes to address the state’s concerns. They will be allowed to continue to sell the plants grown with pesticides but must inform patients that chemicals were used in their growth, he said.

“The state is unable to decide if [the pesticide-treated marijuana is a health issue] because of the lack of research in the industry to know the risks associated with igniting pesticides on cannabis,” Albert said Monday night.

Albert said a death linked to pesticide-treated medical marijuana has been recorded in California, but he did not say when or where that occurred or if the pesticide used in that case is among the nine types found in use in Maine. He described the pesticides found at the Maine marijuana cultivation facilities as “general use pesticides” that are used commonly in agriculture.

Maine Department of Health and Human Services, which oversees the state’s medical marijuana program, did a surprise inspection of the marijuana cultivation operation in Auburn, located at 33 Omni Circle, on March 4 and reportedly found pesticides, a lack of proper security and the production and sale of an illegal and stronger form of marijuana called kief or keefer.

A second surprise inspection also was conducted at a marijuana cultivation facility in Thomaston run by Wellness Connection.

Wellness Connection, which has dispensaries in Brewer, Hallowell, Thomaston and Portland supplied by marijuana from the two facilities in Auburn and Thomaston, will continue to operate, Albert said. The company has around 2,400 patients, he said.

Wellness Connection, which runs half of the state’s medical marijuana clinics, must now contact all prior and current patients to tell them pesticides were used in the products they purchased or are purchasing, and that they have stopped using the chemicals designed to keep bugs away.

The list of deficiencies at the two cultivation facilities pertained to security, governance, inventory control and disposal of excess or unused products.

To keep their license, Wellness Connection must complete 17 tasks, which include resolving conflicts with the board of directors, submitting to frequent inspections, provide weekly status reports, improving security, implementing an inventory tracking system, acquiring a food establishment license for making tinctures and other food products, and mailing the pesticide notice to all former and current qualifying and registered patients and providing the state with a copy of the mailing list.

The final requirement of the two-year consent agreement is troubling to Paul McCarrier, legislative liaison for Medical Marijuana Caregivers of Maine, who estimates between 4,000 and 6,000 Mainers are using medical marijuana.

“The biggest issue is the loss of patient confidentiality,” he said by phone Monday night. “Wellness Connection agreed to give DHHA all their patients — past and present. Pesticides aside, it totally goes against the intent [of the medical marijuana laws].”

Wellness Connection employees “are now using manual methods to control those pests” and must continue to inform patients that they are purchasing marijuana that was treated with pesticides until that supply is depleted, Albert said.

State leaders decided not to shut down the cultivation facilities, basically because the pesticides found are not banned for agricultural use and they have been in use since the facilities opened about a year ago and no one in Maine has reported being sickened by smoking or consuming the plants, Albert said.

Patients, who should contact their doctor if they have concerns, now have to decide if the benefit of the medicinal marijuana outweighs the potential threat, the licensing and regulatory services director said.

“What was important to us was to allow patients to make that decision themselves,” Albert said.

Patients who are worried about the pesticides can turn to other clinics, he said.

“There are four other dispensaries in the state who can absorb some of this … or they can go to a caregiver,” Albert said.

Becky DeKeuster, executive director of Wellness Connection, did not immediately return messages left Monday night for comment. Albert said she admitted to knowing about the pesticides on March 4, and told state investigators that she was in the midst of looking into the matter herself.