ST. PAUL — Local residents may have been the key to convince area lawmakers to support legalizing medical marijuana.

The Minnesota state Senate passed a bill Tuesday legalizing medical marijuana that is more ambitious than Gov. Mark Dayton and law enforcement officials have said they would support.

By a vote of 48 to 18, senators approved the legislation that would make Minnesota the first state to prohibit patients from smoking marijuana to ease their symptoms.

Sen. Dan Sparks, DFL-Austin, supported the bill.

“If we can get that to those with some chronic pain, then I think that would be a good step,” Sparks said on Wednesday. He had heard concern from local law enforcement and at first wasn’t sure whether to support the bill as proposed.

Yet Sparks said he’s pleased by the restrictions embedded in the current Senate bill, which he believes will help deter people from abusing medical marijuana in pill or oil form. He also said hearing from many local residents on the issue helped him form a decision.

“It was surprising how many local people have called and talked about how medical marijuana would benefit a family member who was suffering,” Sparks said. “If we can try to give them a little relief, hopefully it will be a step in the right direction.”

Twenty-one other states and the District of Columbia have legalized medical marijuana, but none has such a restriction.

The Minnesota House expects to consider its medical-marijuana measure on Friday.

Both pieces of legislation ban smoking marijuana and would allow patients to use marijuana in the form of pills, oil and vapor.

State law-enforcement groups oppose any proposal that would allow plant material in the hands of patients. They say legalizing the possession of the marijuana plant, even for medical reasons, would lead to wider distribution of the drug. Police, prosecutors and sheriffs say, among other things, that it would lead to more drugged-driving incidents and ultimately wind up in the hands of children.

“We’re tremendously opposed to the Senate approach,” said Dennis Flaherty, executive director of the Minnesota Police and Peace Officers Association. “The House bill is much different. In that bill, you do not get raw crude marijuana. In the Senate bill, (patients) are allowed to have 2.5 ounces of marijuana.”

Flaherty also praised the tighter control over marijuana in the proposed House bill. Patients could obtain medical pot at only one facility in the state. The Senate bill stipulates 55 alternate treatment centers that would grow, harvest, process and dispense marijuana beginning on July 1, 2015.

Dayton said on Monday that law enforcement’s opinion on the bill was only one consideration in determining his final stance.

“Are the people who need to be helped going to be helped? Are the people who need to be protected going to be protected?” Dayton asked.

Many medical marijuana patients argue the smoking prohibition is shortsighted. Some conditions, such as chemotherapy-induced nausea, render patients unable to consume the drug in pill or oil form. Smoking is a method that provides immediate relief, and it doesn’t require an expensive vaporizing machine to provide the necessary dose, they say.

“A vaporizer is cumbersome,” said Pat McClellan, 47, a Burnsville resident who uses one to treat his mitochondrial myopathy, a type of muscular dystrophy. “It takes both hands to use and the high-end ones, which don’t break like the other ones, can cost $500 to $700.”

Several Republican senators and the Minnesota Family Council, a Minneapolis-based nonprofit, opposed the bill. They argued that the U.S. Food and Drug Administration should approve marijuana for medical use before Minnesota legalizes it.

“If we’re going to listen to someone who (just) says he’s a doctor, why don’t we rely on snake oil, bloodletting and the ever-popular leeching,” said Sen. Warren Limmer, R-Maple Grove, during the debate.

Supporters of legalization including some doctors, scientists, several Minnesota lawmakers and parents of ill children argue that years of evidence exists from many states where medical marijuana is legal that the drug relieves disease symptoms when no other medicine does. They also say the U.S. Drug Enforcement Administration and the National Institute on Drug Abuse continue to hold up medical marijuana research because it’s classified among the most dangerous drugs, which is why so few government-approved studies exist.

The Senate proposal would put the Minnesota Department of Health in charge of implementing the state’s medical marijuana program.

Patients must apply for a photo-identification card and must suffer from a specified set of conditions caused by maladies including epilepsy, cancer and glaucoma. The patient must be examined by a medical doctor or doctor of osteopathy. That doctor must issue a written opinion that the patient likely would benefit from marijuana treatment.

The path to the Minnesota medical marijuana deal has been fraught.

A House bill halted in March when Dayton offered the idea of a research study that likely would take years over legislation that would have provided medical pot for those who need it within months.

Health Commissioner Dr. Edward Ehlinger and Department of Human Services Commissioner Lucinda E. Jesson have opposed legalizing medical marijuana from the beginning. Ehlinger and many doctors say no genuine data exist that proves the drug’s medical efficacy. And Jesson, among others, said marijuana is addictive and can be damaging to teens.

The medical marijuana proposal was revived last month after Dayton challenged state lawmakers who he said “have hidden behind their desks” while he took the heat for his efforts to reconcile all sides in the debate.

Austin Daily Herald contributed to this report.