The U.S. Environmental Protection Agency‘s final rule on emissions from oil refineries could cost operators up to $1 billion, the American Petroleum Institute (API) said this week.

However, API Downstream Group director Bob Greco also welcomed what he called “substantial improvements” since the EPA proposed the new air pollution standards last year.

“EPA analyses, supported by extensive industry monitoring data, show that air emissions from refineries are already at safe levels,” Greco said. “The refinery industry has proven we can provide reliable American energy while protecting the environment and local communities, and collaborative efforts by API and the EPA led to final regulations that are more cost-effective than the proposal.”

The new regulations are designed to further control the release of toxic air pollutants, such as benzene, from oil refineries. The rules also for the first time require refineries to monitor and report levels of benzene at the boundaries of their properties, and to take corrective action if levels are too high.

Other requirements will virtually eliminate visible flare emissions and releases by pressure release devices by requiring process changes and pollution prevention measures for these emission sources. The rules also cover emissions from storage tanks and delayed coking units.

According to the EPA, the updated standards will cut emissions of toxic air pollutants by 5,200 tons per year, and volatile organic compounds (VOCs) by 50,000 tons per year. At the same time, the standards are projected to eliminate emissions of greenhouse gases equivalent to approximately 660,000 tons per year of CO2.