When was the lead reference level changed to 3.5 ug/dL?

The lead reference level was changed to 3.5 micrograms per deciliter (ug/dL) in Fall 2021. This adjustment reflects a growing concern about the effects of lead exposure, particularly among children, and was motivated by new research indicating that even lower levels of lead in the blood can pose health risks. The revision aimed to better align public health initiatives with the latest science regarding lead exposure and its impact.

While various other timeframes may be associated with different lead exposure guidelines or activities, the specific change to the reference level was officially implemented in Fall 2021. This shift emphasizes the public health objective of reducing lead exposure among vulnerable populations, especially young children. The timing also matches broader trends in public health policy that emphasize precautionary measures to protect against toxic exposures.