Skeptics of genetically modified food gathered in Carlsbad on Wednesday morning, May 28, to meet with staff for state senator Mark Wyland. They sought his support for SB-1381, a bill that would have required food suppliers to disclose whether their products are wholly or partially derived from genetically modified organisms, or GMOs.

A similar measure, 2012's Prop 37, failed by a narrow margin of 51.4% to 48.6% when put before voters, after major food suppliers and chemical companies poured $45.6 million into an ad campaign blasting the initiative, outspending their opponents by a margin of more than 5-to-1.

Prop 37 would have been the first labeling mandate in the United States, though virtually every other developed nation on the globe has had similar laws on the books for years. Since then, however, Vermont's state legislature has passed a GMO labeling law of its own, despite threats of litigation from the Grocery Manufacturers' Association industry trade group. Two Oregon counties have banned farming using genetically modified seeds, and a statewide labeling measure set to go before voters in November is picking up steam.

"You can't prove safety, you can't prove that there's no difference [between natural and GMO crops]" says Solana Beach resident and GMO labeling proponent Adrienne Samuels, arguing her case. "There's no long-range research that proves GMO crops don't affect humans over a period of time. But there is research that indicates that there are problems.

"The industry always counters that research with their own science that they've paid for. They'll put forth a study that fails to find that GMOs are toxic. But if you develop the wrong study, if you look in the wrong place, of course they'll fail to find evidence that they're toxic."

Corn is the most common GMO crop deployed across the U.S. today, with a popular variant being chemical giant Monsanto's "Roundup-ready" seed line. The seeds are designed to be resistant to Monsanto's Roundup plant killer, allowing it to be sprayed indiscriminately in a field, attacking only invasive weeds, leaving the crop to grow unfettered. But in the years since its introduction, the weeds themselves are developing a resistance to the herbicide, causing a continual increase in the amount of chemicals that need to be sprayed on crops to achieve the desired effect.

"The meeting went very nicely," said Samuels of her visit with Wyland staff, but "there was nothing that, to me, suggested that [Wyland] would be voting one way or another."

It turns out that the group was unable to reach Wyland in a meaningful way — he was among a majority that failed to pass the bill despite more support than dissent, with a final afternoon vote with 19 in favor, 16 opposed (with 6 legislators abstaining and 2 votes needed to reach a majority). Marty Block, who represents a large swath of central San Diego, also opposed the bill.

(updated 5/30, 2:35 p.m.)