Hilcorp, Exxon and Conoco Top Greenhouse Gas Emitters, Environmental Groups Say

The groups said the rankings could inform investors, natural gas buyers and policy makers who can more easily compare the pollution track records for emissions data that has been measured and evaluated in different ways.

“Oil and gas producers are not equals when it comes to methane emissions,” said Andrew Logan, senior director of oil and gas at Ceres, in a press release.

Many companies within the industry have committed to reducing greenhouse gas emissions, including setting specific voluntary targets.

The American Petroleum Institute, a trade group that represents Exxon Mobil, ConocoPhillips and Occidental, has broadly supported new Biden administration regulations under way to cut methane leaks from oil-and-gas operations, though they have asked regulators to change some parts of the proposed rules.

On its website, Hilcorp said that its “business model stresses the acquisition and efficient operation of late-in-life oil and gas properties…. Hilcorp’s ability to reduce infrastructure, modernize and optimize equipment, and increase production while safeguarding the environment…is our business model.”

Hilcorp and Exxon Mobil didn’t immediately respond to a request for comment.

An API spokesperson disputed the report’s assertion that companies aren’t working hard to reduce methane emissions.

“Our industry is at the forefront of data collection and advancing and utilizing cutting-edge technologies, including remote monitoring with satellites and lasers, to detect and reduce methane emissions and any suggestion to the contrary is false,” the group said.

The report released Thursday was generated using data that the 300 largest U.S. oil and gas producers submit to the U.S. Environmental Protection Agency, which tracks major emitters of methane, carbon dioxide and nitrous oxide, the groups said.

The report found that emission releases from producers varied because of a company’s equipment choices and operational practices.

Higher portions of carbon dioxide came from companies that burn off natural gas through a disposal practice called flaring, or the burning off of excess gas. A higher proportion of methane came from companies that use pneumatic equipment such as valves, which can release a small amount of natural gas to operate.

Greenhouse gases such as carbon dioxide and methane are emitted from the oil and gas drilling process, including from wells and pipelines. Agriculture and landfills are also a major source of methane emissions.

Houston-based Hilcorp, which says it is the largest privately owned oil and natural gas producer in the U.S., topped the list for both methane emissions and greenhouse gas emissions overall.

Last year, the Biden administration proposed new regulations that could require companies to replace leaky, older equipment and buy new monitoring tools to sharply reduce emissions of methane. The rules are expected to be completed within the next year.

Lesley Feldman, senior analyst at Clean Air Task Force, said the report underscores the need for such regulations, which could decrease the wide range of pollutants that come from operators with proportionally large emissions, compared with lower-emitting peers.

“There are clear steps oil and gas producers can take to reduce their methane and other greenhouse gas emissions,” she said in a statement.

The report’s authors said the amounts of emissions released by producers are higher than what is reported to the government, because the figures don’t account for giant accidental releases of methane. They also exclude emissions from smaller facilities whose operations fall below reporting requirements.

Major companies have voluntarily tried to cut back on methane leaks, recovering gas that they can sell to customers. Last month, however, the House Committee on Science, Space and Technology released a report that said companies are using leak detection equipment “in a limited and inconsistent manner.”

Rep.

Eddie Bernice Johnson

(D., Texas) said she is disappointed that producers are underusing detection methods such as drones, continuous monitoring cameras and satellite sensors that can help cut emissions.

“We simply cannot achieve our emission reduction goals if we do not address methane leaks happening within our own country,” she said in a statement that accompanied the report.

Write to Katy Stech Ferek at katherine.stech@wsj.com