Exxon Mobil must turn over decades’ worth of documents showing how much the company knew about climate change. The decision was taken yesterday by a Massachusetts judge in an investigation brought by the state’s attorney general Maura Healey.

In 2015, reports by Inside Climate News and the Los Angeles Times showed that Exxon played down the risks of climate change after its own scientists revealed what those risks would be as early as 40 years ago. Following the reports, Haley and New York’s attorney general launched an investigation into the oil company to determine whether Exxon misled its shareholders and the public in regards to its knowledge of climate change.

Exxon had requested a protective order exempting the company from handing over the climate change documents, but Massachusetts Superior Court Judge Heidi Brieger denied it, marking a win for Healey.

This order affirms our longstanding authority to investigate fraud. @exxonmobil must come clean about what it knew about climate change. https://t.co/3zxesrge0k — Maura Healey (@MassAGO) January 11, 2017

An Exxon spokesperson told Reuters that the company was "reviewing the decision to determine next steps." The decision came the same day as the Senate’s confirmation hearing for Exxon CEO Rex Tillerson, whom President-elect Donald Trump nominated as secretary of state.

At the hearing, Tillerson was asked about climate change and whether he believed it was caused by human activity. Tillerson didn’t directly answer the question and instead replied, "The increase in greenhouse gas concentrations in the atmosphere are having an effect. Our abilities to predict that effect are very limited."