January 17 will be a big day for the Centers for Disease Control. It appears their meeting will be discussing a proposal to lower the threshold level for lead exposure.

According to Reuters, the US CDC will be 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.

According to Scientific American, the CDC has been using a blood lead threshold of 5 micrograms per deciliter for age under age six since 2012. The CDC sets public health standards for exposure to lead. However, while there's no level of lead exposure is safe for children, those who test at or above that level warrants a public health response.

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

But the step, which has been under consideration for months, could be controversial. One concern is evident: lowering the threshold could drain sparse resources from the public health response to children who need the most help, as in those with high lead levels.

The CDC did not respond for a request to comment.

Exposure to lead, typically in peeling old paint, tainted water or contaminated soil, can cause cognitive impairment and other irreversible health impacts.

The CDC adjusts its threshold periodically as nationwide average levels drop. The value is meant to identify children whose blood lead levels put them among the 2.5-percent of those with the heaviest exposure.

Lead has no biological function in the body, and so the less there of it in the body, the better, according to Bernard M Y Cheung, from the University of Hong Kong.

The federal agency is talking with state health officials, laboratory operators, and medical device makers and public housing authorities about how and when to implement a new threshold.

Since lead has been banned in paint and phased out of gasoline nearly 40 years ago, average childhood blood lead levels have fallen more than 90-percent. Now the average is around 1-microgram per deciliter.