Attorney General Eric Schneiderman subpoenaed the company on Wednesday evening, demanding extensive financial records, emails and other documents, a source familiar with the investigation said on Thursday.

Exxon on Thursday said it was weighing a response to the subpoena. The company has included information about the business risk of climate change for many years in its quarterly filings, corporate citizenship report and in other reports to shareholders, company spokesman Richard Keil said.

The New York Times first reported the news on Thursday. (nyti.ms/1HuEJC8)

The Exxon investigation might expand to other oil companies, according to the people with knowledge of the case, though no additional subpoenas have been issued, the newspaper said.

Sources told the New York Times that the attorney general's investigation began a year ago and encompasses company filings dating back to the 1970s.

Last month, a broad array of environmental groups demanded the U.S. Department of Justice investigate Exxon after reports by Inside Climate News and the Los Angeles Times said the company's own scientists raised worries about global warming decades ago only to see their findings doubted by executives.

However, Ken Cohen, vice president of public and government affairs at Exxon, has accused environmental groups of deliberately cherry-picking facts. He said on Thursday that for nearly 40 years the company has worked with governments and universities to develop climate science in a transparent way.

Since 2009, the company has supported what it calls a revenue-neutral carbon tax as the preferred policy for reducing emissions.