HOUSTON — The largest U.S. oil refinery released 8 million pounds of illegal pollution in the last five years, violating federal air pollution laws thousands of times, according to a lawsuit filed Tuesday by environmental groups.
The lawsuit against ExxonMobil is the latest by Sierra Club and Environment Texas as part of their campaign to rein in what they call "illegal emissions" by dozens of refineries and chemical plants that operate in the Texas Gulf Coast. In recent months, the groups have reached multimillion-dollar, out-of-court settlements with Shell and Chevron Phillips after filing similar suits. The groups say this is the largest of the lawsuits based on the size of the plant.
ExxonMobil denied the allegations and said it would fight the lawsuit. The company said it had invested $1 billion in recent years to improve emissions.
The lawsuit accuses Exxon of violating emission limits on sulfur dioxide, a component of acid rain; hydrogen sulfide, a toxic, flammable gas characterized by a rotten egg smell; such cancer-causing agents as benzene and butadiene; carbon monoxide; and the smog-causing agent nitrogen oxide.
The legal maneuvers are part of the broader accusations by the environmental groups and the U.S. Environmental Protection Agency that state regulators are not properly monitoring and enforcing federal emissions standards.
Texas has more oil refineries, chemical plants and coal-fired power plants that any other state and is the nation's leader in greenhouse gases. The state produces more than 20 percent of the nation's oil and one-third of the country's gas is refined along the Texas Gulf Coast.
Texas environmental regulators say their rules are meant to decrease pollution but are not so stringent that it becomes too expensive to operate in the state.