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The Copper Conundrum

California and Washington state are vying to lead the nation in reducing environmental harm from copper-based bottom paints.
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When I first painted the hull of my boat, the bottom job was long overdue (and had been since before I bought her four years earlier). I blushed with embarrassment as the Travelift revealed her sea-worm and barnacle-encrusted state to passersby.

Like many newbies, I was book smart, but not boatyard seasoned about the job at hand. I did know that a main active antifouling ingredient in most bottom paints is copper, but I was in Washington, a state that enacted a law to ban copper-based antifouling paints. The ban was supposed to take effect 2021, the following year.

With my boat up on jack stands, I zipped up my coveralls and gave the label on my paint can one last scan. Its contents did, indeed, contain copper.

How Did Copper Get in There?

“Copper was one of the primary ingredients in antifouling compounds dating well before the 1770s, when the British Royal Navy began implementing a system of overlapping copper plates tacked in with copper nails on the bottoms of their ships,” says Saxon Bisbee, vessel manager and nautical archaeologist of the Northwest Seaport Maritime Heritage Center in Seattle.

According to Bisbee, most other navies adopted and used the system until iron and steel hull construction became the norm starting in the 1860s. Since then, bottom paints have continued to incorporate copper compounds.

“Copper has the advantage of being one of few metals which do not corrode in seawater, and is malleable and easy to work,” Bisbee says. “Copper oxide, the greenish coating copper acquires when exposed to oxygen, is toxic to marine life. So up to a point, it keeps things from growing on hull bottoms. With wooden ships, this also added an extra bit of protection in keeping away shipworms.”

Copper again gained popularity after tributyltin biocides came under widespread scrutiny and bans in the 1980s. But today, more states than just Washington are looking at copper with a critical eye.

In 2018, the California Department of Pesticide Regulation championed a regulation that placed a leach rate cap on copper antifouling paints. Aniela Burant of the department’s Surface Water Protection Program said studies had shown high concentrations of copper in California marinas, posing a threat to aquatic organisms. “It is important that alternative paints are available to boaters,” Burant added. “It is also important that those alternative paints are effective and will not cause adverse effects to nontarget organisms.”

“I’m not convinced moving to a copper--free environment is better,” says Peter Schrappen, government affairs director of the Northwest Maritime Trade Association. The devil we don’t know in copper substitutes is worth considering. A report about marine paints and their effects on the environment is due in 2024.

“If Washington state is the only state to be copper-free, then it’s the same hurdles as with the previous attempted phaseout,” Schrappen says. “Companies are not going to bring forward a suite of products for a state that’s 24th in the country in boat registrations. And if they did, there’s still the question about the detrimental effects of those new toxic chemicals on shellfish and salmon.”

While most marine organisms that attach themselves to hulls can be scraped off, barnacles grow into the surface and form dense calcium deposits underneath the paint.

While most marine organisms that attach themselves to hulls can be scraped off, barnacles grow into the surface and form dense calcium deposits underneath the paint.

What Should Boaters Do?

For now, it’s only boaters in Washington and California who are directly affected by changing copper regulations. David Dickerson, vice president of state government relations for the National Marine Manufacturers Association, says there is little to report about copper regulations east of the Mississippi River.

“The NMMA believes it is essential for boaters to continue to have access to the antifoulant paint formulas that are environmentally safe and work best in their waters where they use their boat,” Dickerson says.

At the same time, the federal Environmental Protection Agency may look to results in California and Washington as examples to expand upon.

“We want to see reductions in copper concentrations across the state because that will lead to protections of aquatic organisms,” Burant says. “The combined use of lower-leach-rate copper paints, best-management-practice cleaning methods, and alternative paints will help accomplish that goal.”

Aniela Burant, senior environmental scientist at the California Department of Pesticide Regulation

Aniela Burant, senior environmental scientist at the California Department of Pesticide Regulation

Burant adds that boaters are free to make eco-friendly choices regardless of legislation: “There are many copper--based antifouling paints that are available to boaters. There are also noncopper biocidal antifouling paints, as well as biocide-free alternatives that are available for use.”

Bisbee says Northwest Seaport has relied on antifouling paints from local shipyards for at least five decades. “These almost certainly contain copper compounds,” he says. “I am all for efforts to better protect the integrity of Puget Sound waters. Hopefully, this will be able to balance the needs of the shipping, fishing and naval industries in this region, which are the industries which led to non-native settlement here in the first place.”

As for my bottom job, I used an affordable, copper-based brand that a few local salts recommended. After a week of sweating, sanding, rolling and tipping through a respirator mask, I was glowing with pride as my boat was once again loaded onto the Travelift, this time bound for the water.

I think about the next job, probably a few years off thanks to the cold Puget Sound waters, and wonder what my bottom paint options will be. Will I go copper-free with a worthy eco-friendly substitute, or will the decision be made for me?