MONTPELIER, Vt. – With time ticking down in this year’s Vermont Legislative session, it’s becoming clear that lawmakers won’t pass a bill requiring labels on genetically modified food before wrapping up their work for 2013.

The House Judiciary Committee isn’t expected to finish its work on the measure and send it to the full House for debate until next week. On Friday afternoon, committee members were digging into the legal weeds, examining opinions from the Hawaii attorney general, an industry group and legislative lawyers in Oregon on how well such a measure might hold up in court.

With just a week or two left on the legislative calendar, supporters of the GMO labeling bill said their best hope was to get a positive vote in the House before adjournment and to ask the Senate to tackle the issue when lawmakers return for the second year of their two-year biennium in January.

Sen. David Zuckerman of Burlington, vice chairman of his chamber’s Agriculture Committee, said Friday that there was no chance his panel would be able to review the GMO labeling bill and bring it to the full Senate for debate before the end of the 2013 session.

Lawmakers are tentatively scheduled to finish up their work by next Friday. There was widespread speculation that the session may extend into the following week if negotiations over several open bills drag on.

Andrea Stander, executive director of the farm advocacy group Rural Vermont, said by January, “the landscape may have changed significantly,” with action on the issue in other states. Among those are Connecticut, where legislation is pending, and Washington state, which is set to vote on a referendum in November calling for labeling of food containing genetically modified components.

The Vermont bill would do that for most foods, but would exempt animal products, including meat and dairy products. That’s despite the fact most Vermont dairy cows are fed corn from genetically modified seed, according to members of the House Agriculture Committee.

Among the concernsis the likelihood that a Vermont law on GMO labeling could draw a lawsuit from the biotech industry. At issue would be whether the compelled speech of required labeling would violate the First Amendment.

Fears of a lawsuit are real for many lawmakers. Vermont’s liberal Legislature in the past decade has passed progressive legislation on campaign finance reform, trying to close the state’s lone nuclear plant and restricting the collection by “data mining” companies on doctors’ habits in prescribing medications, only to see them struck down in federal courts, often at the cost to the state of millions of dollars.

Michael O’Grady, an attorney with the Legislature’s Legislative Council legal research staff, told lawmakers Friday that the GMO bill appeared to be defensible in court, but said the range of legal opinions from Hawaii and Oregon indicate there are no guarantees.