The U.S. Centers for Disease Control and Prevention is considering lowering its threshold for elevated childhood blood lead levels by 30 percent, a shift that could help health practitioners identify more children afflicted by the heavy metal.

Since 2012, the CDC, which sets public health standards for exposure to lead, has used a blood lead threshold of 5 micrograms per deciliter for children under age 6. While no level of lead exposure is safe for children, those who test at or above that level warrant a public health response, the agency says.

Based on new data from a national health survey, the CDC may lower its reference level to 3.5 micrograms per deciliter in the coming months, according to six people briefed by the agency. The measure will come up for discussion at a CDC meeting Jan. 17 in Atlanta.