A top official from the U.S. Centers for Disease Control and Prevention says the agency should have reacted sooner to concerns about hazardous fumes in the government-issued trailers housing thousands of hurricane victims.

Howard Frumkin, director of the CDC’s National Center For Environmental Health, told a congressional panel in Washington on Tuesday that problems with formaldehyde levels in trailers date back to the 1980s.

The problems seemed to “recede,” he said, until the Federal Emergency Management Agency used tens of thousands of travel trailers to shelter victims of hurricanes Katrina and Rita in 2005.

Frumkin said the CDC didn’t tackle the issue “as aggressively and as early” as it should have after Katrina.