WASHINGTON — Lawmakers assailed Environmental Protection Agency chief Scott Pruitt on Thursday for the ethics and spending scandals that have prompted bipartisan calls for his ouster. On the defensive, the EPA chief said “half-truths” and “twisted” allegations were an effort to undermine the Trump administration’s anti-regulatory agenda. The public grilling at a House hearing came as support has eroded for Pruitt among fellow Republicans after a nearly monthlong hammering of negative headlines about outsized security spending, first-class flights and a sweetheart condo lease.