WASHINGTON, Sept. 10 (UPI) -- U.S. Sen. Bill Nelson, D-Fla., said Thursday the federal investigation into the use of defective Chinese-made drywall in his state is moving too slowly.

Following a briefing, Nelson said he spoke with the Consumer Product Safety Commission, the Environmental Protection Agency and the Centers for Disease Control and Prevention regarding the drywall problem, The Miami Herald said.

"I asked how harmful is it, and they said, 'We've got to wait till the end of our study,'" said Nelson, who wants Chinese-made drywall to face a recall in Florida. "But when are you going to have some definitive information?"

Nelson, who has also proposed such drywall goods face a temporary ban in his state, said asked U.S. President Barack Obama to make the drywall goods a top priority during the head of state's upcoming visit to China.

The use of Chinese drywall in U.S. homes has been linked to health and structural problems. As many as 50,000 homes in Florida may be affected, the Herald reported.

The Environmental Protection Agency said testing showed the drywall has lower levels of certain substances compared with plasterboard made in the United States. The Chinese goods reportedly also contain substances not found in the U.S. drywall goods.