Katrina was one of the worst natural disasters in U.S. history, in part because of a breakdown of leadership and response at the city, state and federal level. Congress passed the Post-Katrina Emergency Reform Act in 2006 to give FEMA more responsibility and to put in place safeguards to mitigate against another failed response.

The signatories said FEMA under President Donald Trump has strayed far from the disaster preparedness reforms designed to correct the agency's mistakes in responding to Hurricane Katrina in 2005.

FEMA employees on Monday warned Congress that the Trump administration's changes and leadership at the agency could harm the U.S. if disaster strikes.