President George W. Bush’s choice to head the Environmental Protection Agency on Friday canceled a controversial program to test the effects of bug spray and other pesticides on infants after two Senate Democrats threatened to block his confirmation.

Sens. Barbara Boxer of California and Bill Nelson of Florida said they would place a “hold” on the White House’s nomination of acting EPA administrator Stephen Johnson unless he canceled the $9 million program, which would have paid families $970 to videotape how spraying insecticides in their homes affected infants.

Boxer and Nelson said the program put children at risk.

Questioned by Boxer at a Senate Environment and Public Works Committee hearing on Wednesday, Johnson said he suspended the Children’s Environmental Exposure Research Study last year before it began pending an independent review. But he did not commit to Boxer’s request to cancel it.

“I have concluded that the study cannot go forward, regardless of the outcome of the independent review,” Johnson, a career EPA scientist, said in a statement.

The committee will vote on Johnson’s confirmation on April 13.

The EPA had defended its children’s environmental exposure study as important to help the agency understand how kids are exposed to pesticides that are common in American homes. The research project plans to examine the homes of selected children in Duval County, Florida, and will give participants a camcorder, children’s clothing and a $970 payment.

“Information from the study was intended to help EPA better protect children,” Johnson said on Friday. “EPA will continue to pursue the goal of protecting children’s health.”

The research project, which is partially funded by the American Chemistry Council, does not require the participants to buy or use any additional pesticides than what is already in their homes.