A Pittsfield woman has sued a former employer for not rehiring her after she told them she uses marijuana for medical reasons.

The American Civil Liberties Union of Maine and Augusta attorney Walter McKee filed the lawsuit Tuesday in Somerset County Superior Court, on behalf of Brittany Thomas against Adecco Group North America, a global temporary staffing and recruiting agency.

“No patient should be forced to choose between the pain relief she needs to live a normal life and the employment she needs to support her family,” said Zachary Heiden, legal director for the ACLU of Maine. “And no employer should be forcing itself into the middle of a decision best made by a patient and her doctor.”

Thomas, 24, had been employed with Adecco in September and October 2011 and was assigned to United Technologies Corporation in Pittsfield where she assembled smoke detectors. She was let go when there was no more work, but was called back months later and asked to return to work. Thomas was eight months pregnant at the time and told them she would have to wait until at least a month after the baby was born.

Prior to the pregnancy, she suffered from severe back pain caused by arthritis, bulging discs, an annular tear and a pinched nerve, among other things. She said she was originally prescribed narcotic pain medication that had side effects and failed to relieve her pain. She stopped taking the drugs while pregnant and after she gave birth in March 2012, didn’t want to go back to narcotics. Her doctor suggested medical marijuana.

By early April, she was a certified medical marijuana patient. She had been using for a short time when she went back to Adecco for work and she disclosed the fact to her employer.

Once the test came back positive, though, Thomas was told she would not be rehired.

“Using medical marijuana would never have gotten in the way of me doing my job, because I never would have taken it while on duty,” Thomas said. “I choose to use medical marijuana to control my pain because it doesn’t have any of the side effects of stronger pain medication, like addiction. The incredible thing is, if I was using a stronger drug, I could have kept my job.”

Maine is an at-will state, which means an employee may be terminated for any non-discriminatory reason. The complaint argues that Thomas was discriminated against as a medical marijuana user and the company was wrong not to consider Thomas for employment because she did not violate any laws. She is seeking unspecified damages, including back wages.

Heiden said the ACLU approached Adecco about settling out of court but “those discussions were not fruitful.” A spokesman for Adecco, a global Fortune 500 company with 6,600 offices worldwide, said she was not aware of the lawsuit and that it was premature to comment. The company has 20 days to file a response to Thomas’ complaint.

Maine voters passed a limited medical marijuana law in 1999 and then expanded it significantly in 2009. Mainers with qualified medical conditions now can grow their own marijuana, buy it from one of eight nonprofit dispensaries or buy from a certified caregiver who is permitted to grow marijuana for as many as five patients.

“Adecco is ignoring the will of the people of Maine, who overwhelmingly approved the use of marijuana for serious medical conditions,” McKee said. “No employer should be permitted to flout state laws protecting the right of patients to access the medicine they need.”

Heiden said there is limited legal precedent for this type of case, at least in Maine, and that’s one of the reasons the ACLU has gotten involved.

The issue has come up in many of the other 17 states that allow some use of medical marijuana.

The 6th Circuit U.S. Court of Appeals in Michigan ruled last October that private employers may terminate someone’s employment for failing a drug test without violating that state’s medical marijuana laws. That decision came after a man sued his employer, Wal-Mart, after failing a drug test.

Last December, a New Mexico woman sued her employer after claiming that she was fired for participating in her state’s medical marijuana program. A Denver man who was fired in 2010 from his job as a telephone operator after failing a drug test because of medical marijuana has sued his employer. Both cases are pending.

The state of Arizona passed a law in 2011 that says an employer may not base any employment decision on an applicant’s or employee’s status as a cardholder or as a registered qualifying patient or user of marijuana under the Arizona Medical Marijuana Act. However, the same law shields some employers from liability if they fire employees who are under the influence of marijuana while on the job.