Environmental Protection Agency head Andrew Wheeler said he was not involved with the Justice Department’s decision to launch an antitrust investigation against four automakers that joined with California on fuel efficiency rules, a move that Democrats have questioned as possible retaliation by the White House.

“I knew nothing about the DOJ antitrust until it hit the press,” Wheeler told the Washington Examiner during an interview Wednesday at his EPA office. “I did not know. We did not coordinate on any sort of antitrust investigation.”

Congressional Democrats have asked the Trump administration to turn over documents showing whether the White House directed the Justice Department to investigate Ford, BMW, Honda, and Volkswagen for making voluntary agreements with California to follow fuel economy standards stronger than what the Trump administration plans to set.

Sen. Kamala Harris of California has requested a Justice Department inspector general investigation into the matter.

The Justice Department is seeking to determine whether the automakers broke federal competition laws by partnering with California. Democrats say the investigation was politically motivated, without merit, and a retaliation for automakers rejecting the Trump administration.

Wheeler’s EPA has pursued its own aggressive tactics against California in recent months. In September, the agency sent a letter to California air regulators questioning whether the state has the legal authority to strike a deal with four automakers on fuel standards.

It is also challenging the Trump administration’s move to eliminate California’s power to set its own greenhouse gas limits for cars that are stronger than federal standards. And it has threatened to withhold highway funds and permitting approvals from California until the state agrees to redo more than 100 air quality plans.

Wheeler, in the interview, denied the EPA is retaliating against California or unfairly targeting the state.

“We’re not punishing the state at all,” Wheeler said. “But we are asking the state to refocus to make sure that they are protecting the air and the water for their residents, which they really haven’t been doing as much. They have been focusing more on climate change.”