A petition drive has started to seek a statewide public vote on a proposed law that would legalize marijuana in South Dakota as a medical treatment for severe and chronic pain.

If supporters get 16,776 valid signatures by April 6 next year, the proposed law will go on the general election ballot in 2010.  A similar measure narrowly failed after getting about 48 percent of the vote in the 2006 election.

The new proposal would legalize the limited use of marijuana to treat symptoms of illnesses that include pain and the nausea that can accompany chemotherapy treatments for cancer.