New Hampshire's Department of Health and Human Services says about 300 families were sent an erroneous letter saying a blood test for their children showed elevated levels of lead.
The department's Division for Public Health Services apologized for the error in a news release Wednesday.
It said the false notification was the result of a processing error.
The incorrect letters from the department's Healthy Homes and Lead Poisoning Prevention Program said a test result showed the children had a blood-lead level of 3 micrograms per deciliter, or higher. The department said that corrected letters were being mailed that say the blood-lead level test result showed no exposure above the 3 micrograms.
The department said it is "working diligently" to make sure no additional letters are sent to parents in error.
