The Republican chairman of the House science committee is threatening to subpoena a group of Democratic state attorneys general for all information related to their climate change investigations into Exxon Mobil.

Science, Space and Technology Committee Chairman Lamar Smith, R-Texas, sent letters Wednesday to some of the state attorneys general leading the probe, and said his committee is ready to use "compulsory" means "to obtain responsive documents in the possession, custody, or control of your office."

The letters were sent to New York Attorney General Eric Schneiderman, Massachusetts Attorney General Maura Healey and a number of environmental groups.

"If you continue to refuse to provide information responsive to the committee's requests on a voluntary basis, I will be left with no alternative but to utilize the tools delegated to the Committee by the Rules of the House of Representatives," Smith said in the letters.

Smith had sent letters twice in recent months to all 17 of the attorneys general, asking them for all communications related to climate change and the investigation into Exxon Mobil.

The AGs began issuing subpoenas to the company earlier this year after a series of news reports showed the company had covered up data compiled by its own scientists that showed climate change had created a substantial risk to its business.

The state attorneys general say the act constitutes fraud, and places the public at risk.

In the last week, however, Exxon Mobil has experienced some victories after filing motions against the AGs in a number of federal district courts. The attorney general for the U.S. Virgin Islands, Claude Walker, agreed to withdraw his subpoena in a major blow to the Democrats' climate probe.

Exxon Mobil says the investigations violate the company's rights and protections under the Constitution.