As a part of the pre-employment medical examination, Carleton was required to use headphones to listen to and identify different tones and different decibel levels. For the first iteration of the test, the examining nurse did not permit Carleton to use his hearing aids. The nurse then administered the test again, this time allowing Carleton to wear his hearing aids, even though their use was not permitted under the standard.

Three days later, Carleton was notified that he had failed the hearing examination. He appealed this determination to the division of human resources, stating that he had worn hearing aids for 15 years, was currently a member of the Stowe fire department and had never had a problem carrying out his duties as a firefighter/EMT. As a result of this appeal, the division asked Dr. James Ryan, the medical director of Boston Medical Center's Occupational and Environmental Medicine Department, to examine the test results.

Ryan concluded that, in his opinion, the testing was accurate based on the history of Carleton's disability and on the “wide margin by which Carleton failed the test.” He went on to say that hearing aids are not permitted to be used while testing. He explained that the reasons for the prohibition were that hearing aids do not permit accurate localization of the direction of sounds; can be swamped by loud background noise; may be subject to failure due to electronic malfunction or weak batteries during an emergency situation; and may act as radio receivers, picking up interference from nearby radio transmitters. Ryan added that “loss of effective hearing in such a situation … would place the life and safety of the firefighter and the public in danger.” Consequently, the division sent Carleton a letter denying his appeal because he had “failed to meet the public safety medical standards for municipal firefighters.”

Carleton subsequently filed an employment discrimination claim alleging handicap discrimination. He contended that the division should have allowed him to meet the hearing standards with the assistance of his hearing aids, arguing that he was “a qualified individual with a handicap who was capable of safely performing the essential functions of the job of firefighter with the reasonable accommodation of being permitted to wear hearing aids.” He did not claim that he could perform the essential functions of the job of a firefighter without the use of these hearing aids, or that the level of hearing acuity set by the medical standards is unnecessary to the performance of those functions.

Carleton then consulted with Dr. David Citron, a hearing expert whom he had retained in conjunction with his discrimination case, to do further testing. That testing appeared to show that even with the use of hearing aids, Carleton's hearing did not meet the division's standards. However, Citron explained that Carleton's hearing aids did not fit his ears perfectly during this examination and that the misfit likely accounted for the test results. At the doctor's suggestion, Carleton's hearing aids were sent back to the manufacturer for repair. Carleton then visited Citron for a follow-up evaluation with hearing aids that had been repaired and fit his ears properly. After this test, Citron concluded that Carleton had the hearing ability necessary to “perform the duties of a firefighter with no difficulties.”