Investigators ask former EPA chief to turn over private emails

While Ms. Jackson was chief of the agency, employees were repeatedly reminded about the rules for private email use, the lawmakers said.

Ms. Jackson and the EPA have been fending off accusations about inappropriate email use for months after Christopher Horner, a researcher affiliated with the Competitive Enterprise Institute, uncovered a secondary official government address Ms. Jackson used under the alias “Richard Windsor.”

Mr. Horner questioned whether Ms. Jackson was using that secondary address to avoid public scrutiny.

But the latest revelation involves another account that Ms. Jackson kept as her personal, private email.