Louisiana activists battling a polluting chemical and plastics industry are claiming a victory in a community just outside Reserve, where the Guardian has investigated high cancer rates and toxic emissions from a nearby factory.

The Chinese company Wanhua Chemical has withdrawn an approved application to build a $1.25bn facility in Convent, in the face of an appeal against its plans and a lawsuit from local residents.

“My great-great-great-great grandmother came out of slavery and bought my family’s land,” said Barbara Washington, a member of the group Rise St James, whose home is near the proposed site. “Our hard work has paid off. We will not stop till all those industries who want to come in here change their plans. We are tired of being sick. We refuse to be sick any more. Don’t even try to come into St James. We will not allow it.”

The site for the proposed site was in St James parish, just outside Reserve, which is the focus of a year-long reporting series by the Guardian, Cancer Town, which is examining local residents’ fight for clean air in a locality the Environment Protection Agency says has a cancer risk that is 50 times above the national average. The plant in Reserve, the Pontchartrain Works facility, is the only place in America to produce the synthetic rubber neoprene, and emits the chemical chloroprene, which is classed as a “likely carcinogen” by the EPA.

Sharon Lavigne, president of Rise St James, called the withdrawal “a victory for all of us in St James parish”. She and others opposed the plant because they said it would unfairly pollute the air in African American districts and lower property values.

“We aren’t just going to sit back and accept that it’s open season for industry to build in St James parish. We are ready to fight,” she said.

“David beats Goliath,” the group’s press release proclaimed.

Wanhua wanted to produce the type of plastic used for car parts on the banks of the Mississippi River. Global oil and chemical industries are preparing for a surge in plastics production, even as the material streams into the oceans and piles up in developing countries. The Trump administration supports the industries’ growth.

Rise, the Louisiana Bucket Brigade and other campaign groups have been fighting for clean air in Convent and in Reserve, predominantly black towns.

The groups also oppose another far bigger planned plastics facility from the Taiwanese company Formosa Plastics in St James parish. The project would consist of 14 plants.

Formosa has sought permission to double toxic chemicals released into the air in the parish.

Lavigne said the chemicals industry locates in black communities to avoid pushback.

“They never had anyone go up against them before. No organizations went up against the parish council or the industry to stop this. All I heard is it couldn’t be stopped because it’s a done deal,” Lavigne said. “We stopped them.”