When voters go to the polls tomorrow, there will more than just candidates on the ballot. There are also 146 referenda and initiatives in 41 states and the District of Columbia, including a handful that relate to science, engineering, or the environment. They include questions asking voters to fund a new $21 million genomic medicine research center in Maine, to approve a $125 million bond for a new engineering building at the University of Rhode Island, and to allow terminally ill patients in Arizona to use experimental treatments.

Two ballot issues have stirred particularly strong debate—and an outpouring of cash. In Colorado and Oregon, groups are spending millions of dollars to sway votes on the question of whether companies should be required to label foods containing genetically modified organisms (GMOs). In Michigan, hunting and conservation groups are engaged in a heated and complicated battle over whether to allow the hunting of wolves.

The GMO labeling initiatives—Proposition 105 in Colorado and Measure 92 in Oregon—have attracted strong opposition from industry groups, who argue there is no evidence that GMO foods pose a health threat and that labeling would be costly to consumers. “Once you start to label, now you have to segregate every single step of the way—the field, silo, transportation,” says Martina Newell-McGloughlin, a biotechnology researcher at the University of California, Davis, who is allied with groups urging a "no" vote on Proposition 105. “You’re going to end up paying a tax for a label that has no health value.”

Larry Cooper, director of the Right to Know Colorado GMO campaign, which is urging a "yes" vote on Propositon 105, rejects that idea. He argues that labeling costs would be low and that consumers should be fully informed about what is in their food.

So far, pro-labeling forces have prevailed in just one state in recent years; Vermont enacted a GMO-labeling law earlier this year. And food industry and agriculture groups are spending heavily to prevent another state from requiring labels. In Colorado, they’ve donated more than $11 million to defeat Proposition 105; the "yes" forces have raised less than $500,000. In Oregon, the spending gap is smaller: antilabeling forces have raised more than $16 million compared with about $7 for pro-labeling forces.

In Michigan, the conflict is over wolf hunting. Officials removed endangered species protections for the state’s gray wolves in 2012, prompting a state senator named Tom Casperson to successfully push legislation that would designate the wolf as “game species.” Antihunting groups responded by collecting enough signatures to challenge Casperson’s measure on this year’s ballot, and many observers predicted they would win, in part because the state’s voters in 2006 rejected a similar effort to allow hunting of doves. Pro-hunting forces responded with another legislative maneuver, however, forcing their opponents to add a second ballot measure. But the maneuvering didn’t end there: Pro-hunting legislators then pursued a successfully pursued a third legislative gambit to sidestep both ballot measures. The upshot: Even if voters approve the two antihunting measures, known as Propositions 14-1 and 14-2, the wins may not be enough to bar wolf hunting. The matter could end up in the state’s courts.

Some wolf biologists, meanwhile, say the outcome may not make much difference to the state’s wolf population of about 650 animals. Hunters killed just 22 wolves in the first hunt in 2013, fewer than the limit of 43 set by state officials.

Other science-related items on Election Day ballots include: