On Tuesday the Senate Agriculture Committee approved the Safe and Accurate Food Labeling Act, also known as SAFE, which would prevent states from passing mandatory food labeling laws for genetically modified organisms, including one such law scheduled to go into effect July 1 in Vermont.

Fourteen of 20 members of the committee, including three Democrats, voted in favor of the markup of the bill by Chairman Pat Roberts, R-Kan.

Opponents of the bill, who call it the Deny Americans the Right to Know Act, or the DARK Act, say it preempts state law and keeps consumers from getting information they want about their food. The legislation, which does not prevent companies from providing voluntary labeling, will now go to a vote on the Senate floor.

“Let the buyers make up their mind,” said Sen. Patrick Leahy, D-Vt., who voted against the bill. In the committee meeting, he also said the legislation was too rushed. “You seem to be saying to the world that GE producers have something to hide.”

But legislators who supported the bill cited estimated costs that manufacturers would pass on to consumers to comply with mandatory labeling as well as a potential burden on farmers and ranchers. In addition, they thought mandatory GMO labels would imply to consumers that genetically modified foods are not safe, even though government agencies have said they are.

“We can’t ignore advances in science,” said Sen. Amy Klobuchar of Minnesota, one of the Democrats who voted in favor of the bill. She also expressed concern about inconsistencies among existing state GMO labeling laws; for example, Vermont’s exempts dairy products from GMO labeling whereas one in Connecticut does not.

“I don’t think we can have this patchwork of laws,” she said.

In a statement issued after the bill was approved, California Sen. Barbara Boxer urged fellow senators not to pass it.

“This is a sham bill that will deny American families the right to know what they’re feeding their kids,” she said.

Boxer has been a proponent of other GMO labeling measures such as California’s Proposition 37, which voters rejected in 2012.

In a phone interview, Scott Faber of the Environmental Working Group, one of several groups in favor of GMO labeling, said that “asking companies to provide American consumers this information isn’t asking them to do any more than they’re already doing for two-thirds of the world’s consumers, who live in countries with mandatory GMO labeling.”

Tara Duggan is a San Francisco Chronicle staff writer. Email: tduggan@sfchronicle.com. Twitter: @taraduggan