Officials haven't been able to confirm whether the crews were exposed to any of the hazardous materials present on the shuttle, said Cynthia Sage, a U.S. Forest Service spokeswoman.
Three of the 46 searchers were taken to the hospital after being affected by fumes during Sunday's search. The team was composed of two 20-person teams of wilderness firefighters, along with NASA and Environmental Protection Agency officials.
Searchers described a hole in the ground that was emitting a chemical smell.
``We had two crews out in that area, and they had severe reactions that varied from headaches and nausea to vomiting,'' said Sage. ``Three people were taken to the hospital, and they were treated and released.''
The shuttle broke apart over East Texas on Feb. 1, killing all seven astronauts. Its debris is being assembled so investigators can figure out what went wrong.