On Monday, the first day of the Republican National Convention, the GOP platform committee chair was met with a chorus of laughter when he mocked the Democratic party for including climate justice — the part of environmental justice that deals with climate change and greenhouse gas emissions — in their party platform.

“There’s sections about that they call ‘climate justice’ — climate justice!” Sen. John Barrasso (R-WY) said, drawing attention to the Democratic Party’s newly-published platform that considers environmental justice to be a key tenet of good environmental policy.

There is no small amount of irony in the fact that Republicans are mocking the concept of environmental justice during a convention that takes place in Cleveland. For years, Cleveland has been at the center of the United States’ domestic environmental policy — and while Republican delegates and politicians joke about climate justice and abolishing the EPA, the city of Cleveland is dealing with environmental problems that pollute its air and poison its residents.

The birthplace of the EPA

Donald Trump, the New York businessman and presumptive Republican presidential nominee, has previously said that, if elected president, he would abolish the Environmental Protection Agency, calling the department’s actions “a disgrace.”

But it was a Cleveland environmental disaster that took place nearly half a century ago that prompted the formation of the EPA — and the creation of the Clean Air Act and Clean Water Act.

In 1969, an oil slick on the heavily polluted Cuyahoga River caught fire in Cleveland, causing some $100,000 worth of damages. It wasn’t the first time the river, which had been polluted from years of heavy industry, had caught fire, but taken in tandem with a growing environmental movement and massive oil spill in Santa Barbara, the event gained national attention and became a galvanizing cry for politicians that wanted to do more to regulate pollution and protect the environment. One year after the Cuyahoga River fire, in 1970, President Richard Nixon established the EPA. Two years later, despite a presidential veto, both houses of Congress came together to pass the Clean Water Act.

“Cleveland is the home of the Clean Air and Water Act,” Rick Smith, a radio host who grew up in Cleveland, said while attending the Republican National Convention. “You don’t see the Cuyahoga River catching on fire anymore. You see a thriving ecosystem here in the lake. I can’t see going back on that kind of progress.”

Indeed, the Cuyahoga River’s revitalization has been a success story for both the EPA and the Clean Water Act. Ecosystems have once again begun to take hold, with more than 40 species of fish found in the river.

Persistent problems

But the cleaning up of the Cuyahoga River is just one success in a more complicated picture of Cleveland’s environmental legacy — and persistent problems.

Cleveland has some of the worst air in the country, with year-round particle air pollution levels ranking as the 11th worst out of 220 metropolitan areas rated each year by the American Lung Association. Much of this pollution can be attributed to emissions from cars, as well as emissions from coal-burning power plants. Living in areas with high levels of air pollution has been linked to heart disease, chronic pulmonary disease, and developmental diseases in young children. Ironically, it is the EPA, which Trump said he would dismantle as president, that most directly regulates air pollution, through programs like the Clean Power Plan and the Mercury and Air Toxic Standards, which deal with pollution from power plants, and Corporate Average Fuel Economy (CAFE) standards, which deal with pollution from vehicles.

“When you don’t have clean air, look at the prevalence of asthma,” Rep. Stephanie Howse, who represents Cleveland in the Ohio State Assembly, told ThinkProgress from the convention. “It impacts people, which then correlates to high absentees of our babies in schools. It is a very cyclical approach that happens when we don’t have a good environment.”

Cleveland also suffers from high levels of lead poisoning, tied to a legacy of old, untreated lead paint in homes. According to the Cleveland Plain Dealer, more than 40,000 children in Cuyahoga County have been poisoned by lead in the last 15 years, and the vast majority of those children live in Cleveland. In 2003, the Ohio Legislature created the Lead Poisoning Prevention Fund, aimed at combating lead paint in older homes, but the fund was never given any money. Today, more than 14 percent of children in Cleveland test positive for elevated levels of lead in their blood. Some studies have linked childhood lead exposure to violent crime, while others have linked lead exposure to developmental delays in young children.

While one party mocks, another acts

Environmental justice is just one area in which the Republican and Democratic party platforms greatly diverge — but set against the backdrop of Cleveland, the disparity becomes all the more striking. Hillary Clinton, the presumptive Democratic nominee, released a plan in April aimed at combating environmental injustices, with a particular focus on lead abatement. Trump, for his part, refused to comment on the water crisis in Flint.

Some climate activists, however, are not content to let Trump remain silent on issues of environmental justice. The group 350.org has planned actions to coincide with the final day of the Republican convention on July 21. The actions are meant to draw parallels between civil rights movements, like #BlackLivesMatter, and the climate crisis, which experts say will disproportionately impact low-income communities and communities of color.