PORTLAND — Some emergency medical service workers in Maine spoke out against a COVID-19 vaccine mandate because of concerns that it would lead to ill-timed staff shortages.

The Maine Board of Emergency Medical Services held a public hearing on the subject on Monday. Democratic Gov. Janet Mills announced new rules earlier in August that require all health care workers to be vaccinated against COVID-19 by Oct. 1.

Kyle Baker, a paramedic with Winthrop Ambulance Service, said “there are people who are willing to walk away” over the mandate. The new rules apply to firefighters and ambulance crews, as well as other health workers.

More than 600 people participated in the virtual meeting, and most who spoke were against the mandate. A common concern among the speakers who opposed the mandate was that would exacerbate emergency worker shortages.

Some speakers said they also feared burned-out workers who have complied with vaccine guidelines might quit because of an even heavier work burden.

Mills has said the health worker mandate is about “protecting health care workers, their patients, including our most vulnerable, and our health care capacity.”

The debate is taking place as the state grapples with rising cases of the coronavirus.