The smell emanating from the New York Organic Fertilizer Company in Hunts Point defies description. The plant, which converts 60 percent of the city’s sewage into fertilizer pellets, has been drawing angry protests from neighbors for years.

Melanie Dunston lives a few blocks from the sewage treatment plant. Her 4-year-old daughter has asthma and symptoms of bronchitis. “It stinks,” she said. “It’s too disgusting for my kids to go out and play. And now it’s affecting their health.”

In a rally last week, she and 75 other South Bronx residents chanted outside the gates of the plant, pinching their noses to shut out the stench that wafted from inside.

Complaints about the plant’s odor are nothing new. Neither are accusations that its emissions cause asthma, a claim countered by plant management’s assurances that they fall well within legal limits. What made Tuesday’s rally unusual was that four formerly disparate groups worked together to plan it: the South Bronx Clean Air Coalition, Mothers on the Move, the Point, and Sustainable South Bronx.

Jaime Rivera of the South Bronx Clean Air Coalition says new blood in some of the organizations has fostered cooperative attitudes. “To be honest, there’s been friction between groups in the past, because we don’t always agree on how to get results,” he said. “But now we decided the important thing is to fight together on the issues we do agree on.”

What they agree on is a need for cleaner air. The South Bronx is home to several large industrial operations, also including four New York Power Authority plants. A study conducted in 1996 by the U.S. Environmental Protection Agency showed that the number of people with asthma in the South Bronx is 10 times higher than the national average.

“The problem is there is no law to regulate the cumulative emissions from all of these plants,” said Manuela Arciniegas of Sustainable South Bronx. “Working together with other groups, maybe we can get a wider perspective.”