DENVER (CN) — Four environmental groups sued Interior Secretary Ryan Zinke on Thursday to protect the two-state Dinosaur National Monument from increased air pollution from oil and gas drilling.

Established in 1915, the Dinosaur National Monument encompasses 200,000 acres from Rio Blanco County in northwest Colorado to northeast Utah counties Duchesne and Uintah. An estimated 300,000 people a year visit the park’s 1,500 fossils exposed on the cliff face inside the Quarry Exhibit Hall, spending around $18 million in local economies.

According to lead plaintiff Rocky Mountain Wild, the Uinta Basin already “suffers from unhealthy ozone levels due to emissions from extensive oil and gas development.” But in December 2017 and June this year the Bureau of Land Management approved an additional 121 oil and gas leases on 117,720 acres, including some parcels within 3 miles of the monument.

Under the Clean Air Act, the EPA has designated the Uinta Basin “an ozone nonattainment area.” The environmental groups consider the obvious culprit the 11,000 producing wells leased across Rio Blanco and the Uinta Basin.

Plaintiffs include the National Parks Conservation Association, the Center for Biological Diversity and WildEarth Guardians. Their lead counsel is Stuart Gillespie with Earthjustice in Denver.

“Oil and gas developers accidentally leaking or intentionally venting methane into the air contributes to climate change,” according to the 45-page lawsuit. “Other hydrocarbons vented and leaked by oil and gas development are hazardous air pollutants that are toxic to humans, including known carcinogens like benzene.”

In addition to its noxious effects on humans, ozone pollution also stunts vegetation growth.

“During the winter, inversion layers trap nitrogen oxide and volatile organic compound emissions from oil-and-gas development in the basin, causing a build-up of exceedingly high levels of ozone. As a result, the Uinta Basin’s air quality has degenerated to a level that is sometimes worse than even the most polluted days in urban areas like Los Angeles and Denver,” according to the complaint.

The Tucson-based Center for Biological Diversity boasts on its website: “We’ve sued Trump 88 times and we’re just getting started.”

“Zinke’s playing a dangerous game by skipping environmental reviews at the risk of human lives,” said Diana Dascalu-Joffe, a senior attorney at the Center for Biological Diversity. “It’s appalling that he’d push for more fossil fuel extraction on public lands and then ignore how much damage fracking would do, particularly to kids with asthma. The Trump administration’s drilling and fracking agenda is a disaster for people and wildlife alike.”

In addition to the plaintiffs’ commentary, BLM received comments from the National Park Service and 13,000 members of the public “raising concerns about the lease sale’s impacts on air quality, public health, and the environment,” which were inadequately addressed in the bureau’s environmental assessment, according to the complaint.

“This case is about enforcing our environmental laws, which are designed to protect public health, the environment and treasured places like Dinosaur National Monument,” said lead attorney Gillespie. “BLM cannot circumvent these laws in its headlong rush to lease our public lands for oil and gas development. We’re asking the court to hold the agency accountable and set aside these illegal leasing decisions.”

The groups seek declaratory judgment that the leases violate the National Environmental Policy Act and the Federal Land Policy and Management Act, were issued arbitrarily and capriciously and beyond statutory authority, and want them vacated, plus costs of suit.