If adopted by government officials, hundreds of thousands more children could be diagnosed with lead poisoning. The change would be the first time the government has tackled the issue in more than 20 years.
Recent research persuaded panel members that children could suffer harm from concentrations of lead lower than the old standard, officials at the Centers for Disease Control and Prevention said. Too much lead is harmful to developing brains and can mean a lower IQ.
In 1978, the government banned lead in paint, and the number of lead poisoning cases under the old standard has been falling.
The Wednesday vote would lower the definition of lead poisoning for young children from 10 micrograms of lead per decilitre of blood to five micrograms.
The Advisory Committee on Childhood Lead Poisoning Prevention voted 11 to one to recommend the change. The CDC has three months to act on the advice. The agency has accepted all of the panel's recommendations in the past.
Usually, lead poisoning cases involve children living in old homes that are dilapidated or under renovation, who pick up paint chips or dust and put it in their mouths.
In 2009, researchers reported that 1.4 per cent of young children had elevated lead levels in their blood in 2004, the latest data available. That compares with almost nine per cent in 1988.