(CNN) Ethics watchdogs, federal auditors and congressional committees are conducting nearly a dozen inquiries into Administrator Scott Pruitt's actions at the Environmental Protection Agency.

The probes are reviewing his travel expenses, personal security, and other allegations of ethical concerns, such as Pruitt's below-market-rate lease with a lobbyist couple, one of whom represented a client before the EPA.

Pruitt and the EPA have largely defended his actions, saying decisions were made by his subordinates and that, in some cases, "processes will be changed going forward."

"I'm not afraid to admit there's been a learning process and when Congress or independent bodies of oversight find fault in our decision making, I want to correct that and ensure that it does not happen again," Pruitt told lawmakers at a recent hearing.

Here are the probes into Pruitt: