What is the risk of lead exposure in infants living in homes built before 1978 and what are the recommended screening tests for infants under 6 years old?

Homes Built Before 1978 Require Lead Risk Assessment in Infants

All homes built before 1978 should be presumed to contain lead-based paint hazards and warrant blood lead screening in infants and young children, with homes built before 1960 posing the highest risk. 1

Housing Age and Lead Hazard Risk

The year 1978 is the critical cutoff because lead-based paint was banned from residential use in the United States at that time. 1, 2 However, the risk stratifies significantly by decade:

• Pre-1940 housing: 67% contain one or more lead paint hazards 1
• 1940-1959 housing: 39% contain lead paint hazards 1
• 1960-1977 housing: 11.4% contain lead paint hazards 1
• 1978-1998 housing: Only 2.7% contain lead paint hazards 1

Houses built through the 1950s used paint with the highest lead concentrations, making pre-1960 homes particularly dangerous. 1

Why This Matters for Infant Screening

Infants and toddlers face peak exposure risk between 6-36 months of age due to normal mouthing behaviors, increasing mobility, and more efficient lead absorption compared to older children and adults. 1 Blood lead levels typically:

• Increase rapidly between 6-12 months of age
• Peak between 18-36 months of age
• Then gradually decrease 1

Iron deficiency further increases lead absorption in young children, compounding the risk. 1

Screening Recommendations

Children living in pre-1978 housing should be considered high-risk and require blood lead screening, particularly those under 6 years of age. 2, 3 The screening is most critical for:

• Infants and children in homes built before 1960 (highest risk) 1
• Low-income families in older housing 4
• Homes undergoing or recently completing renovation, repair, or painting activities 2
• Homes with deteriorated paint or visible paint chips 1

Critical Exposure Pathways in Pre-1978 Homes

House dust contaminated with lead-based paint particles is the primary exposure pathway, not the intact paint itself. 1 Key sources include:

• Deteriorated interior and exterior paint releasing fine lead dust 1
• Window troughs and sills (often more contaminated than floors due to friction and higher exterior paint lead content) 1
• Soil contaminated by exterior lead paint, tracked indoors 1
• Dust generated during renovation, repair, or painting activities 2

Common Pitfalls to Avoid

Do not assume a home is safe simply because paint appears intact—lack of visible deterioration does not ensure absence of lead-contaminated dust. 1

Renovation and repair activities in pre-1978 homes dramatically increase exposure risk, even when performed by well-intentioned homeowners or tenants. 2 In New York State, 66% of lead-exposure cases from renovation were performed by resident owners or tenants, not professional contractors. 2

Formula-fed infants face additional risk if tap water contains lead from old plumbing, as water can contribute approximately 20% of blood lead levels when concentrations exceed 5 ppb. 1

National Housing Data Context

As of 2011, approximately 37 million (35%) of 106 million U.S. housing units contain lead-based paint. 1 Of the 24 million units with significant lead-based paint hazards, 1.2 million house low-income families with children under 6 years of age. 4