If children are growing up in a home that was built before 1978, there is a chance they can get lead poisoning, according to the New York State Department of Health website. As this poisonous metal was once used in paint and plumbing, it is possible that lead dust could be in the air that children are breathing in.

This, in turn, has the potential to lower their IQ. USA Today highlighted the results of a National Toxicology Program report that found blood-lead levels below 5 micrograms per deciliter can lead to cognitive and academic impairment, attention deficit hyperactivity disorder and losses in IQ.

To better ensure children’s safety, the Centers for Disease Control and Prevention recently announced that for children under 6 years of age, the threshold for lead exposure has been lowered to 5 micrograms of lead per deciliter of blood, The New York Times reported. This is a reduction from the previous standard, which was 10 micrograms per deciliter.

If parents are raising a family in a house or apartment that was built before 1978, they may want to have their children take an IQ test for kids to set a baseline for their cognitive abilities.