Gas pump dripping fuel out of planet earth.

Federal and state officials have fined a Virginia firm $100,000 for operating 73 trucks lacking diesel particulate filters. In addition to the fine, the company will also have to spend $290,000 on programs that support pollution-reduction.

Diesel trucks are a main contributor of smog-forming nitrogen oxide emissions. Jared Blumenfeld, the EPA’s regional administrator, said compliance with the rules is crucial as California currently has the country’s poorest air quality.

California established tough regulations in order to cut down on emissions of toxic diesel soot and smog-forming pollutants from diesel trucks. Estes Express received the first federal action against a company from the Environmental Protection Agency. According to Blumenfeld, Estes was contacted in the spring of 2014, along with about a dozen other trucking companies, to provide information on their compliance with California’s diesel emission rules. As a result, Estes disclosed that approximately %15 of its 500 truck fleet were not equipped with particulate filters. Also, the company failed to specify whether the subcontracted trucks it had hired were in compliance.

“Today we mark the closure of the first of what we hope are many cases,” said Todd Sax, chief of enforcement for the California Air Resources Board, adding that it “sends a strong message that trucking companies, even those based outside of California, must meet California’s requirements when operating here.”

The regulations, which were established in 2008, mandate that heavy-duty diesel trucks must comply with the 2010 engine standards. Alternatively, owners can improve their trucks with filters that lessen diesel particulate emissions. The EPA approved the state’s new regulations and granted them authority to enforce them under the federal Clean Air Act. These rules will be in full effect by 2023, and will affect all operational diesel trucks in the state. There are approximately 1 million diesel trucks affected by these regulations, including the 625 thousand out-of-state registrations.

The Environmental Protection Agency named Estes for the violations in February. Because of this, Estes has made the necessary changes and now only operates newer truck models in the state and complies with the Clean Air Act. In addition, Estes will pay over $250,000 to assist with pollution-reduction in San Joaquin Valley, which is one of California’s most polluted areas. The funds will replace old wood burning stoves with newer and cleaner devices. The company will also contribute $35,000 to support a program to teach diesel regulations to out-of-state trucking firms.

The Environmental Protection Agency foresees other similar settlements involving emissions violations. California air regulators conduct on-road inspections and other investigative measures. These regulations are the strictest in the country and aim to drastically reduce pollution and the resulting health risks. According to state air-quality officials, if the regulations are fully implemented, approximately 3,500 premature deaths will be prevented in California between 2010 and 2025.

“We think that’s an appropriate use of the penalty and we look forward to a compliant future within California,” said Nick Scola, a spokesman for Estes. The company agrees with the EPA’s findings, he said, and is “working diligently” to meet regulators’ requirements.