The men responsible for a controversial study on a toxic, cancer-causing chemical in Federal Emergency Management Agency trailers will find themselves on the hot seat before Congress next week -- and they may be confronted with some uncomfortable new details.

As head of the Agency for Toxic Substances and Disease Registry (ATSDR), Dr. Howard Frumkin and his deputy, Dr. Tom Sinks, oversaw the creation of a report critics say downplayed the health risks of formaldehyde levels in trailers FEMA provided disaster victims in the Gulf Coast region, particularly long-term effects.

A January statement from the agency described the report as "focused on the acute health effects of formaldehyde exposure -- to meet the urgent needs expressed by FEMA in its original request."

Frumkin testified before the Senate last month, where he told lawmakers that while concerns about formaldehyde in the trailers were raised in 2006, they "did not rise on our priority list."

"If I could roll back the tape, I would," Frumkin said then.

In February, the government admitted that the trailers were unsafe and began moving residents to other quarters. At the time, some 100,000 people still lived in the trailers.

Both Frumkin and Sinks have confirmed they will show up for the April 1 hearing before the House Committee on Science and Technology, a Hill staffer said, noting that the committee had uncovered new information on what Frumkin and Sinks knew about their agency’s controversial report.