New York State Attorney General Eric Schneiderman's office demanded that ExxonMobil Corporation give investigators documents spanning four decades of research findings and communications about climate change, according to a person familiar with the year-long probe.

An 18-page subpoena issued to the oil giant late Wednesday seeks documents from Exxon (NYSE:XOM) related to its research into the causes and effects of climate change, to the integration of climate change findings into business decisions, to communications with the board of directors and to marketing and advertising materials on climate change, the person said.

Investigators have been looking closely into the company's disclosures to shareholders and the Securities and Exchange Commission, and the subpoena also sought documents related to those communications. The probe is based on New York's powerful shareholder-protection statute, the Martin Act, as well as the state's consumer protection and general business laws.

"We have received a subpoena for production of documents relating to climate change from the attorney general of New York and are assessing our response," Exxon spokesman Alan Jeffers said in a statement. "ExxonMobil has included information about the business risk of climate change for many years in our 10-K, Corporate Citizenship Report and in other reports to shareholders. We unequivocally reject allegations that ExxonMobil suppressed climate change research contained in media reports that are inaccurate distortions of ExxonMobil's nearly 40-year history of climate research that was conducted publicly in conjunction with the Department of Energy, academics and the UN Intergovernmental Panel on Climate Change."

While investigators have been looking into what Exxon knew about climate change and what it said about it to the public and shareholders for some time, recent investigative news reports by InsideClimate News and the Los Angeles Times made the issue "more ripe," the person said. Lawmakers, presidential candidates, environmentalists and climate scientists have recently begun calling for investigations of Exxon under federal racketeering and securities laws.

"Just as New York's Teddy Roosevelt took on the Standard Oil Trust a century ago, New York's attorney general has shown great courage in holding to account arguably the richest and most powerful company on Earth," Bill McKibben, founder of the advocacy organization 350.org said in a statement. "We hope that other state attorney generals and the federal Department of Justice, and the Securities Exchange Commission will show similar fortitude."

New York's Martin Act forbids "any fraud, deception, concealment, suppression, false pretense" or "any representation or statement which is false" and gives the state broad powers of discovery.

Some climate advocacy groups have long urged that Schneiderman, a second-term Democrat, investigate Exxon and other companies under the 1921 statute.

Schneiderman and predecessors have used that power to probe national and international corporations on the grounds that their securities are traded in New York. Former Attorney General Eliot Spitzer used the Martin Act to prosecute abuses on Wall Street more than a decade ago. Former Attorney General Andrew Cuomo, now the governor, investigated five coal-burning utility companies using it, arguing that they failed to provide a complete picture of climate risks in their regulatory filings. The utilities agreed to make more complete disclosures.

In the subpoena issued Wednesday, investigators requested documents going as far back as Jan. 1, 1977. Included in the request are: