A Lake City man has sued to stop Fourth of July events at the park at the north end of Lake Union until the state shows that gathering to watch fireworks there is safe for viewers, the park and surrounding wildlife.

The city should conduct a thorough environmental review before letting thousands of people watch fireworks from the partially remediated toxic-waste site that is Gas Works Park, an environmental activist says.

A Lake City man has sued to stop Fourth of July events at the park at the north end of Lake Union until the state shows that gathering to watch fireworks there is safe for viewers, the park and surrounding wildlife.

Benjamin Schroeter, who is not an attorney, filed the lawsuit in King County Superior Court, arguing that the city failed to conduct a review in accordance with the State Environmental Policy Act before permitting the annual event.

But city officials maintain that the fireworks display, a once-a-year civic event, is exactly what the state had in mind when it exempted certain activities from environmental review requirements.

And the city already places conditions on the event’s private contractor so nothing happens that might release any contamination during the Independence Day celebration, said Christopher Williams, deputy superintendent of the Seattle Parks and Recreation Department.

“We’ve never done an environmental review” for Fourth of July festivities, Williams said. “But we think we’ve done a good job minimizing the risk.”

Gas Works was once the site of a coal-to-gas plant, which left behind a toxic stew that has caused the park to close several times over the years. In 1984, hazard-testing crews with the Environmental Protection Agency showed up wearing disposable rubber gloves, boots and face respirators. The city later closed the park for five months.

In 1997, the city dug up and hauled away thousands of pounds of tar. Three years later, it pumped out the carcinogen benzene from underground plumes.

In 2007, portions of the park were closed so investigators could better understand tar that kept bubbling up from below.

Schroeter said he fears that all the people showing up at the park at once could kick loose the 18-inch cap of protective soil that helps keep contaminants locked in the dirt. He also wondered why shooting 5,000 explosive shells over Lake Union didn’t require some kind of review to make sure it didn’t hurt fish.

“I’m not trying to stop the fireworks,” he said. “I like fireworks, but the city should do some kind of review.”

Williams said the city would close the park — and has — if it thought it was harmful to the environment or public health.

“Thousands of people use Gas Works every year without something going wrong,” he said. “The reality is the other 364 days of the year, it functions as a park. And looking at fireworks in Seattle is a tradition.”

Even Schroeter said Monday that he thought it was unlikely his petition would get any kind of court review before Saturday.

Williams declined to estimate how many people he thought would watch the fireworks display from Gas Works. Given that Ivar’s Seafood Restaurants is not putting on a show over Elliott Bay this year, Williams said he thought crowds at the park could be larger than normal.

Craig Welch: 206-464-2093 or cwelch@seattletimes.com