Image: FalseStatement: “Study after study has shown that fireworks have virtually no impact on marine life,” San Diego Mayor Jerry Sanders said in a May 31 statement.

Determination: False

Analysis: The annual July 4 fireworks display over La Jolla Cove is in jeopardy.

A Superior Court judge ruled last week that the show and others like it need to comply with the California Environmental Quality Act. Organizers need to determine the environmental impacts of the fireworks and mitigate them if possible. That requires a complicated and costly analysis that can’t be finished in a month.

The mayor has vigorously defended the city’s fireworks displays, blaming the hubbub on what he’s called a misguided crusade by Marco Gonzalez, the Encinitas-based environmental attorney who’s sued over the issue. As Sanders prepared Tuesday to take his case to a national audience on Fox News Channel, his office e-mailed a short statement.

“Study after study has shown that fireworks have virtually no impact on marine life,” Sanders said.

We asked spokesmen for Sanders to provide that evidence. They didn’t respond to two requests.

But there is evidence to the contrary, showing that fireworks can have an impact on marine life.

Gonzalez has filed hundreds of pages of documentation with the city that includes evidence that fireworks hurt marine life. Those are independent studies, not work that Gonzalez has commissioned.

Most notably among them, two federal scientists examining fireworks’ impacts on seabirds in Sonoma County concluded that 2007 Independence Day fireworks there caused a spike in Brandt’s cormorants abandoning nearby nests where they’d been incubating eggs. Seven of 90 nests were abandoned within two days. Seven more were abandoned shortly after. Those cormorants, long, black seabirds, also nest at La Jolla Cove.

The full impact of fireworks’ pollution on marine life below the surface remains an unanswered question. When fireworks explode, they can send metals and other contaminants that don’t combust into the water below. No one knows exactly what impacts they have.

A federal geochemist examining firework shows’ impacts on water quality in an Oklahoma lake from 2004 to 2006 concluded that the fireworks caused a significant but temporary spike in perchlorate levels in the lake. Perchlorate, a chemical used in rocket fuel, can impact human health by interfering with the thyroid, which regulates metabolism. The lake’s levels of the contaminant far exceeded California’s allowable levels for drinking water, but the study said the effect on fish wasn’t clear.

Rick Wilkin, the U.S. Environmental Protection Agency geochemist who authored the study, said in an email that very little information exists in the scientific literature about how fireworks affect water quality. That doesn’t mean there’s no impact — just that it’s not understood.

A local regulator’s analysis of SeaWorld’s fireworks over Mission Bay, for example, found it unlikely that a single small display would pollute the water below so much that it exceeded water quality goals. But samples taken after large events, like the theme park’s July 4 and Labor Day fireworks, did exceed those targets. Some contained high levels of pollutants like arsenic, mercury and other heavy metals, according to a report from the San Diego Regional Water Quality Control Board, the water pollution regulator. Pollutants could also accumulate over time from small displays, it noted.

The mayor cited those SeaWorld monitoring reports during his Tuesday appearance on Fox News Channel. “We have SeaWorld here that does them (fireworks) every night. They found no ill effects from that.”

That’s not accurate. Those reports found water quality goals had at times been exceeded, though the impact wasn’t clear. The monitoring has been incomplete, according to the water board analysis, and insufficient to determine the effect on critters living in the water.

Because his statement wasn’t supported by scientific evidence, we’ve called the mayor’s statement false.

If you disagree with our determination or analysis, please express your thoughts in the comments section of this blog post. Explain your reasoning.

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Please contact Rob Davis directly at or 619.325.0529 and follow him on Twitter:

Rob Davis

Rob Davis was formerly a senior reporter for Voice of San Diego.

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