Ellen Knickmeyer, The Associated Press

WASHINGTON (AP) " The Environmental Protection Agency's inspector general is opening an investigation into Administrator Scott Pruitt's use of multiple email accounts.

Inspector General Arthur Elkins says his office will review the matter despite budget and staff constraints. With the latest announcement, he is conducting about a half-dozen investigative audits of Pruitt's travel, security and other matters.

The request for the email investigation came from Democratic Sens. Tom Carper of Delaware and Jeffrey Merkley of Oregon. Carper released a copy of the IG letter.

The senators asked the IG to review whether Pruitt was complying with federal law and EPA policy when using multiple email accounts and whether all accounts are searched when responding to Freedom of Information Act requests.

A House committee and the Government Accountability Office also are investigating Pruitt.