In the war over E15 that has raged for more than a decade across the United States, the current battle is the widest ranging yet—set off by a promise that President Trump made to Midwest farmers, and leaving just about every owner of a towable boat caught in the crosshairs as prime cruising season gets underway.

At stake is the potential for boaters to wreck their marine engines by accident, simply by pumping the wrong type of fuel into them at gas stations all across America starting June 1.

The “wrong fuel” in question is E15, made from a blend of 85 percent gasoline and 15 percent ethanol, a renewable fuel that comes from corn and other plant materials. E15 can seriously damage marine engines, which are designed to operate on blends of gasoline with 10 percent or less ethanol. Most marina fuel docks don’t sell E15, but roadside gas stations do, creating a challenge for boaters who fuel their trailerable boats at the same time as their vehicles.

Right now, the Environmental Protection Agency restricts the sale of E15 during the warmest months each year—June through September—because of concerns about increased volatility and the release of organic compounds into the atmosphere. A newly proposed rule change would allow E15 to be sold year-round starting June 1, just in time for the height of boating season. If the rule change is approved, then as of this summer, boaters in Southern states who have had to contend with avoiding E15 at pumps during winter months will now face that challenge year-round, and boaters in Northern states who hit the water only during the summertime could encounter E15 at the pumps without even knowing what it is, or the dangers it can pose to their marine engines.

The federal E15 rule change is being proposed following several years of Trump personally backing an expansion of ethanol sales in general: “This is great for our farmers, and it’s a promise I made during the campaign, and as you know I keep my promises,” he told reporters while heading to Iowa in 2018.

Opponents of E15 say the concerns of boaters are being lost in the years-long political debate, but it’s the farmers who have a strong advocate right now in the White House. The ethanol industry has, for years, wanted E15 to be sold year-round, a reality that would mean big bucks for agricultural states that make up a swath of Trump’s political base.

“E15 provides a major opportunity for long-term, rural growth,” Mike Naig, Iowa’s secretary of agriculture, wrote in The Des Moines Register. “There are more than 200 ethanol plants across the heartland, and each one serves as a pillar of economic productivity. They provide rural manufacturing jobs and a key market for Iowa farmers.”

In the current debate, those economic concerns are expected to quash the frustrations of confused boaters, who often can’t even tell when they’re choosing E15 at the gas station, and who don’t want E15 when they understand what it is.

“It’s one label that has to be on the pump saying, basically, ‘Don’t put this in your boat,’” says David Kennedy, government affairs manager for BoatU.S., who adds that E15 is also not recommended for small engines in chainsaws, lawnmowers and the like.

A 2016 Harris Poll found that only 31 percent of Americans understood that higher blends of ethanol could be harmful to small engines.

The Renewable Fuels Association, which represents the ethanol industry, takes the position that “owners of marine equipment and other small engine applications are savvy consumers that can read and understand the label EPA has approved.”

Not so, Kennedy and other E15 opponents insist. Many boaters fail to see the warning label on the pump at all, and instead focus on advertised fuel prices—which typically show E15 as being 3 cents to 10 cents a gallon cheaper than other options, thanks to subsidies that are intended to push the United States toward renewable fuels. E15 pumps are often just marked with a small sticker and sometimes labeled as Unleaded 88, which can confuse boaters who have heard of E15 and want to avoid it.

The ethanol-based fuel is corrosive and automatically voids warranties. Steve Swihart, service manager at G and G Marina in Roach, Missouri, near Lake of the Ozarks, has an entire wall devoted to wrecked boat parts from ethanol-blended fuel. “It’s not just E15; even E10 is bad,” Swihart says. “We just finished another one yesterday where the whole inside of the fuel line, the liner, eroded away. I have a wall of shame of parts here to show my customers the effects. We want people to see what this stuff can do.”

Swihart says the damage ethanol fuels causes inside marine engines and fuel systems looks almost like dry rot. “O-rings, filters, anything plastic or rubber in the fuel system, it just erodes,” he says. “It plugs up fuel filters, carburetors, fuel injectors, all of it.” Boaters who are only out on the water once every few weeks, he says, especially with outboard engines, are at the most risk because as the blended fuel sits idle, it separates in ways that cost one customer with a 40-hp engine about $600 to fix. “I have a lot of customers who are corn farmers,” Swihart says. “We get into heated arguments about it.”

The dangers that E15 pose to boaters have been scientifically proven since 2011, when Mercury Marine and Volvo Penta provided test engines and facilities for two studies on the effects of E15 in marine engines. The U.S. Department of Energy approved the final analysis of the results, which showed “significant problems with outboard, sterndrive and inboard engines,” according to the National Marine Manufacturers Association (NMMA). Some engines were so badly damaged during the E15 testing that the tests couldn’t even be completed. “Results of the reports show severe damage to engine components and an increase in exhaust emissions, reinforcing the recreational boating industry’s concern that E15 is not a suitable fuel for marine engines.”

At the time those study results were issued, E15 was only beginning to be sold at the pumps, Kennedy says, as part of a push that began in 2005 under the George W. Bush administration to blend ethanol into biofuels. The U.S. Congress significantly expanded that mandate in 2007, and by 2011, when the marine-engine studies were sounding alarms, an exemption was made in the federal Clean Air Act so E15 could be sold. “This has not been a partisan issue,” Kennedy says. “This is a regional issue. This is about the farm economy, people who are interested in selling that product.”

Opponents of E15 believe the EPA will go forward with the rule change, which means this summer boaters will have to be vigilant when choosing fuel at the pump. “It’s confusing,” says Nicole Vasilaros, senior vice president of government relations for the NMMA. “I’ve been working on this for years, and I’m still confused at the pump.” 

This article originally appeared in the June 2019 issue.