Maryland is set to become the 20th state to legalize marijuana for medical uses after lawmakers in the state's senate voted Monday 42-4 in favor of setting up a state-run commission that grants licenses to distribute the drug to approved patients.

HB 1101 cleared Maryland's lower chamber on March 25 by a vote of 108-28, and Gov. Martin O'Malley (D) said he intends to sign it into law. O'Malley previously expressed caution over the bill, apparently concerned that the federal government may try to prosecute state employees who facilitate the program, but changed his mind when those prosecutions never emerged in other states.

Unlike bigger medical marijuana programs like California's, which set up a boutique retail industry and allows doctors to recommend the drug for nearly any condition, the bill in Maryland will put academic medical research centers in charge of determining who can apply for access to the drug. State-regulated growing operations would be tapped for patients' supplies.

“This marks a major step forward for Maryland medical marijuana patients and their families,” a spokesperson for the Marijuana Policy Project said in an advisory. “The Assembly's overwhelming support for this important legislation reflects that of the people of Maryland and the nation as a whole. The time has come to allow seriously ill people to obtain and use medical marijuana if their doctors believe it will help them."

Just 19 states and Washington, D.C. currently allow marijuana use for medical reasons. Only Colorado and Washington have opted to tax and regulate the drug similarly to alcohol, although state-sanctioned retail sales to adults over 21 have yet to begin.