Marijuana convictions that predate current Colorado law could be sealed under a bipartisan proposal being floated inside the Capitol — a move, say some lawmakers and marijuana advocates, that could potentially impact thousands of Coloradans.

The proposal, sponsored by Sens. Jessie Ulibarri, D-Westminster, and Vicki Marble, R-Fort Collins, allows anyone convicted of a marijuana offense that would now be legal under Amendment 64 to have their records sealed. Also, a draft of the bill says that a person convicted of “any other marijuana offense” beyond the scope of Amendment 64 would also be allowed to file a petition with a district attorney to have their record sealed. If the district attorney does not object, the court would then be required to seal the conviction record, according to a draft of the proposal.

Amendment 64 went into effect in December 2012 and allows for the possession of up to an ounce of marijuana for Coloradans age 21 and over. Moreover, it allows for adults to grow and cultivate their own marijuana.

“There are tens of thousands of people with previous cannabis offenses that hurt them from getting things like loans, housing and employment,” said Jason Warf, a marijuana advocate and director of Colorado Springs Medical Cannabis Council.

Groups like the Colorado District Attorneys’ Council and the attorney general’s office on Friday offered reservations about the possible legislation.

“It creates a horrible precedent by retrofitting criminal sanctions for past conduct every time a new law is changed or passed,” Carolyn Tyler, a spokeswoman for the AG’s office, said in an e-mail.

In March, Colorado’s Court of Appeals threw out a woman’s 2011 convictions for marijuana offenses that are now legal. The woman was appealing her convictions for possessing less than an ounce of marijuana and possessing marijuana concentrate, among other charges. At the time, the court said its decision applies only to people who were in the midst of an appeal on the effective date of Amendment 64.

Prior to Amendment 64, possession of less than an ounce of marijuana was a petty offense in Colorado, and state law specified conviction for the offense “shall be punished by a fine of not more than $100.”

From January through November 2012, about 4,800 people over 21 years old were charged with petty possession of less than 2 ounces of marijuana, according to a Denver Post analysis of court data for every county except Denver. Only about 900 of those charges resulted in some type of finding of guilt.

“This falls in line with the will of the voters, who by a wide margin, passed Amendment 64,” said Ulibarri, who Friday noted the bill is still receiving edits.