Courtney Cummings, seen here with her daughter, says Richmond, Calif., is her home, but she's moved further away from the Chevron refinery complex in recent years. America Tonight

RICHMOND, Calif. – On Aug. 6, 2012, Courtney Cummings and her family were in their front yard when a massive fire erupted just six blocks away. “There was a big boom,” she said. “I got really scared. I saw this big fireball go in the air and we all took off running into the house.” The fire was at the Chevron refinery, and the smoke and toxic fallout sent more than 15,000 Richmond residents to the hospital with respiratory problems. Many residents insist that the 2012 fire is emblematic of a willful negligence that dates back decades, at the expense of the low-income minorities who can’t afford to leave. But the 2007 election of a Green Party mayor has energized residents against their city’s largest employer and taxpayer, and turned Richmond into one of America’s environmental battlegrounds. It’s a muddy fight; health impacts are hard to trace with certainty, and the underlying issue has enormous stakes: How responsible are corporations to the communities that build up around them?

The medical costs

"We applaud any sincere efforts by Chevron or anyone else that wants to do the right thing,” says environmental activist Henry Clark. America Tonight

Just across the bay from San Francisco’s glittering tech boom, Richmond is tethered to heavy industry, strewn with petrochemical containers and crisscrossed by train tracks. About 80 percent of people living within a mile of the Chevron refinery are people of color, and a quarter of them live below the poverty line, according to a 2009 report. After the 2012 fire, investigators discovered that severe pipe corrosion caused a rupture that sparked the blaze. They also found that Chevron's own inspectors had repeatedly warned the company to replace the aging pipes. Chevron agreed last fall to pay $2 million and pleaded no contest to six charges, including failing to protect employees from potential harm. Chevron refused America Tonight’s repeated requests for an interview, but in an emailed statement, spokesperson Melissa Ritchie said the company has worked more than 1.9 million hours to improve refinery safety since the 2012 fire. She added that Chevron has provided about $10 million to cover medical costs of affected residents, and recently installed a community air monitoring station that can be checked online. "We applaud any sincere efforts by Chevron or anyone else that wants to do the right thing,” said Henry Clark, director of the West County Toxics Coalition, an environmental justice group that works on behalf of minorities. “But that doesn't mean that we give Chevron a blanket approval to continue to increase the pollution.”

The oil giant next door

Peggy Polk is one of the residents who have developed allergies and asthma from living in Richmond, Calif. America Tonight Across the street from Clark's office sits the North Richmond Center for Health. It was funded with a settlement from Richmond-based General Chemical, following another major industrial fire in 1993 that filled the air with sulphuric acid. “I've developed severe allergies, asthma, lung problems,” said Peggy Polk, one of many senior patients here. “Sometimes I come outside and the air is so thick, it takes my breath away. I have to go in and do a breathing treatment.” Though Richmond's childhood asthma rates are twice the national average, it's not fair to connect them to the Chevron refinery alone, said John Balmes, an environmental health sciences expert at the University of California-Berkeley, who studies the impact of air pollution in the Bay Area. Highway traffic and other industrial operations play a part, he said. "Nevertheless, kids in Richmond do have an increased risk of developing asthma, and events like the Chevron fire could be an important exacerbating effect,” he said. But divining the real impact is complicated, he added, because the community here is largely low-income and of color – an already vulnerable population when it comes to health.

Battling big oil

Cummings, a Native American single mother of two, has lived in Richmond for 30 years. The entire family has breathing problems that require them to use inhalers. “I like it here. Richmond is my home. And at the same time there are other cities where there's not a Chevron in your backyard spewing 24/7 toxins into the air and nobody [is] communicating with you,” she said. "This sediment is going into our bodies and was going into my children, who have no protection except me. That's what makes me sad."

A view of the Chevron refinery complex in Richmond, Calif. America Tonight But Cummings said they're not leaving – and neither is Chevron. The company has operated its 2,900-acre Richmond facility for more than 100 years. Its presence is felt everywhere, from the hulking storage tanks that dot the hillside to the billboards that line the streets. Critics say that the company invests very little in Richmond, while its toxic emissions and headline-grabbing accidents take their toll on the population. “I think it was 1991 where there was an explosion at the processing units that sent black clouds of toxic smoke over this community,” Clark recalled. “A lot of people have moved out, not only because of the issues related to Chevron, but crime and the lack of investment in the area." Clark recognizes that Chevron creates jobs and a tax base, but believes the company has a greater responsibility to the community it pollutes. "We get the childhood asthma, the cancer and health problems and Chevron and the other workers get the profits,” he said. “They laugh all the way to the bank and we crawl all the way to the graveyard burying our people."

"It's a case of environmental injustice. It's a case of environmental racism,” Richmond Mayor Gayle McLaughlin told America Tonight. “We see how Chevron operates in Nigeria. We see how Chevron operates in Ecuador. They disregard communities that they feel aren't organized enough or aren't empowered enough to fight back." In 2004, McLaughlin became the first ever Green Party candidate to win a seat on Richmond’s city council. In 2007, she drew national headlines by becoming America’s only big-city Green Party mayor. Some saw her victory as a political aberration; for others, it was a clear referendum against Chevron. Last summer, the city council, led by McLaughlin, unanimously voted to sue Chevron for "years of neglect, lax oversight and corporate indifference to safety inspection and repairs.” “Chevron doesn't care ... The representatives and the executive management of Chevron is, of course, very clear that profits come first, McLaughlin said. “In fact they have been charged with criminal charges and they admitted to them." She called Chevron “a big, bad oil company.” “When we push back, we’re fighting for our lives,” she said. “We are fighting for our dignity as a community that has a right to health and well-being." Chevron dismissed the lawsuit as a waste of city resources and "yet another example of failed leadership." But McLaughlin made an appeal to the U.S. Chemical Safety Board, the federal agency tasked with investigation industrial chemical accidents. In December, the Richmond City Council got a shot in the arm from the CSB, which blamed Chevron for what it judged to be a preventable incident. “In the case of the Chevron refinery fire, the reactive system of regulation simply did not work to prevent what was ultimately a preventable accident,” CSB Chairman Rafael Moure-Eraso said. The U.S. Chemical Safety Board created an animation of what went wrong with the 2012 refinery fire in Richmond:

The CSB went on to recommend sweeping reforms that would compel refinery operators across California to be more proactive in addressing potential risks, with greater input from workers and local government. The petroleum industry slammed the proposal as adding unnecessary confusion. Chevron said transitioning to the new system would in fact “detract” from safety and lead to more accidents. Then, in an unusual twist, the CSB refused in January to adopt the centerpiece recommendation made by its own staff. The two board members who voted against it said the plan needed more study. The board’s chairman called it “a clearly mature, already well-studied” proposal, and the vote “a missed opportunity to promote fundamental change” and “kicking the can down the road.” "We thought it would pass,” said McLaughlin. “It's a proactive rather than reactive model of safety, so it was a disappointment.” With McLaughlin’s term up in November, there are concerns that the hard-won momentum to hold the company accountable may be lost. “I know for a fact that Chevron will put more money than ever into this year's electoral season,” the mayor said. “In 2012, they put $1.2 million into campaigns to attack our candidates. I know that they will be working harder than ever to try and turn us back. But so will we. I am up for the fight. We cannot go backward." Since the Chevron fire, Cummings has moved further away from the refinery. But the trauma of that dark day still lingers, and it has moved her to speak up. “When Chevron happened, the explosion, I was like, ‘Do I take my girls and leave? Do we finally say enough and go back home?’ But we didn't,” she said. "Because, I have a real big problem when people try to take my voice." Correction: An earlier version of the article stated McLaughlin was elected mayor in 2004. She was elected mayor in 2007.