The Massachusetts ballot question would allow patients with debilitating medical conditions such as cancer, AIDS and multiple sclerosis to get permission from their doctors to use marijuana. The plan also calls for the state to register up to 35 nonprofit medical treatment centers around the state to distribute the marijuana.

A proposed ballot question that would legalize the medicinal use of marijuana in Massachusetts is being bankrolled almost entirely by an Ohio billionaire who has backed similar efforts in other states.

Peter Lewis, chairman of auto insurer Progressive Corp., contributed $525,000 to the Committee for Compassionate Medicine, which is supporting the question. That accounted for virtually all the $526,167 raised by the group in 2011.

The Massachusetts ballot question would allow patients with debilitating medical conditions such as cancer, AIDS and multiple sclerosis to get permission from their doctors to use marijuana. The plan also calls for the state to register up to 35 nonprofit medical treatment centers around the state to distribute the marijuana.

A public relations firm representing the committee said the goal of the question is “to ensure that Massachusetts patients have the same access to the necessary medical resources to fight debilitating diseases that are available in sixteen other states.”

With Lewis’s financial boost, the group is hoping to convince voters to approve the measure if it reaches the November ballot.

Critics of medical marijuana initiatives say weakening the prohibition against the drug could send the message to young people that smoking pot is no big deal, ultimately encouraging more teens to experiment with it.

Under the ballot question, the new treatment centers would be authorized to acquire, cultivate, and process marijuana, including the development of related products such as food, tinctures, aerosols, oils, or ointments.

Patients allowed to possess marijuana would be issued registration cards by the state Department of Public Health after a physician determines in writing that they have one of the qualifying medical conditions.

Nothing in the ballot question changes state laws against driving under the influence or forces health insurers to cover the expense of the marijuana.

The bulk of the money contributed by Lewis – $350,000 – went to hire professional signature gatherers to collect the tens of thousands of signatures needed to guarantee the question a spot on the November ballot.

Lewis also is helping fund a campaign in Washington state to legalize and tax marijuana for recreational use. And in his home state of Ohio, Lewis said last year that he was seeking proposals for a medical marijuana ballot issue for 2012.

If the Massachusetts question lands on the November ballot it won’t be the first time that voters here have been asked to change state law regarding the drug. In 2008, Massachusetts voters overwhelming backed a 2008 initiative which decriminalized the possession of an ounce or less of marijuana. The law instituted a $100 civil fine instead.