A new study published Monday in the journal JAMA Pediatrics has found that about 50% of young children who were tested for lead had detectable levels of the element in their blood, according to Medical Xpress.

Most of the children had relatively smaller amounts of lead, but about 2% had a considerably high level.

The study looked at more than 1.1 million children aged 6 and below who underwent lead testing between October 2018 and February 2020.

Experts said these findings are likely to raise public health alarms in the U.S.

Dr. Morri Markowitz of Montefiore Medical Center, who was not part of the study, said, “The broad picture is: Kids have lead in the U.S. For lead, there’s no too low. We want zero.”

Children often get exposed to lead in the environment, through lead paint in older homes, lead pipes that bring water into houses, and lead found in soil outdoors.

The U.S. Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) say there is no level of lead in blood that is known to be safe, according to the U.S. Centers for Disease Control and Prevention and the World Health Organization.

Lead poisoning could lead to irreversible damage to still-growing young children. It could harm the brain and nervous system, causing issues with learning, behavior, hearing, and speech.

The study’s co-author Dr. Harvey Kaufman, who is a senior medical director at Quest Diagnostics said the new study is the first to examine low levels of lead in children’s blood, which was enabled by more sensitive technology.

He said the team was expecting that some children would have detectable amounts of lead in their blood, “but we were surprised that it was half of all children who were tested.”

Dr. Philip Landrigan and Dr. David Bellinger wrote in a corresponding editorial, which also published Monday in the journal, “These findings confirm that we still have a long way to go to end childhood lead poisoning in the United States” and “underscore the urgent need to eliminate all sources of lead exposure.”

The new study found that 1.9% of children tested had blood lead levels of 5 micrograms per deciliter or more, while just over 50% of the kids had detectable levels of lead, mostly between 1 and 2 micrograms per deciliter, according to Medical Xpress.

Dr. Markowitz said, “There’s lead in the environment, and it persists. It’s way better than 50 years ago, in terms of how much lead is out there, but it’s still there.”