Lead is particularly dangerous to children because their growing bodies absorb more lead than adults do, and their brains and nervous systems are more sensitive to the damaging effects of lead. Here's an article for homeowners about lead: https://www.nachi.org/lead-consumer.htm
If a home was built before 1978, there is a good chance it has lead-based paint. In 1978, the U.S. federal government banned consumer use of lead-containing paint. Lead from paint, including lead-contaminated dust, is one of the most common causes of lead poisoning. Here's information for home inspectors about lead: https://www.nachi.org/lead-facts.htm.
The US EPA regulates lead-based paint activities. Visit the US EPA website for information about inspections, risk assessments, project design, and abatement activities at https://www.epa.gov/lead/lead-based-paint-abatement-and-evaluation-program-overview.
If you perform lead inspections, here's an agreement for lead inspections.