Childhood Lead Risk Factor Metadata: Pre 1950 Housing


Pre 1950 housing estimates are from the U.S. Census Bureau’s decadal census (2000) or the American Community Survey (2016-2020).

Dates Available:

2000 and 2016-2020

Geographic Resolution:

State, County, High-risk Area, and Town


The Maine EPHT Program obtains pre 1950 occupied housing estimate data from the U.S. Census Bureau.  This dataset contains counts of occupied housing units built before 1950. The data are stratified by geographic resolution, and housing status (own, rent).

The dataset contains the following measures:

  1. Percent of housing units built before 1950
  2. Number of housing units built before 1950


This data set supports efforts to improve public health in Maine and contributes to the U.S. CDC’s National Environmental Public Health Tracking (EPHT) Network. A key activity of participants in this network is to track and make available environmental health measures on state and national data portals. Measures derived from the data set described here can be used to compare the prevalence of pre 1950 housing across the state, between groups of people, over time, and in relation to risk factors, exposures, and health outcomes.

The Maine Tracking Network, a member of the National EPHT Network, connects communities, public health professionals, policy makers, state agencies, and others to the data they need to monitor public health, respond to health concerns, prioritize resources for public health action, and evaluate prevention activities. Maine tracks certain health effects, exposures, and environmental hazards that have known relationships, as well as some health effects and environmental hazards that have suspected relationships. By making health and environmental data available through the Maine Tracking Network, more people have access to data they need to think critically and hypothesize about health outcomes and their relationships to conditions in the environment.

Supplemental Information:

Elevated blood lead levels in young children have been associated with adverse health effects ranging from learning impairment and behavioral problems to death. Because children may have elevated BLLs and do not have any specific symptoms, CDC recommends a blood lead test for young children at risk for lead poisoning.  Risk factors identified in the National Health and Nutrition Examination Surveys (NHANES) include income below poverty level and living in housing built before 1950.

A family is defined as two or more people living in the same household who are related by birth, marriage, or adoption. A housing unit is owner occupied if the owner or co-owner lives in the unit. All occupied housing units which are not owner occupied whether rented for cash rent or occupied without payment, are classified as renter occupied.

Maine pre-1950 housing data were available through the U.S. Census Bureau’s decennial census for 2000. Housing data for 2016-2020 were available through the American Community Survey (ACS).  ACS is a relatively new survey conducted by the U.S. Census Bureau. It uses a series of monthly samples to produce estimates for small areas (census tracts and block groups) that were formerly surveyed via the decennial census.  In order to analyze small area data, five years of data were used to produce census block group information specific to Maine.

Entity and Attribute Overview:

This dataset includes the following fields: census/survey year, the number and percent of occupied housing units built before 1950, the number and percent of owner occupied housing units built before 1950, the number and percent of renter occupied housing units built before 1950, the total number of occupied housing units, the total number of owner occupied housing units, and the total number of renter occupied housing units.

Data Limitations:

  • Caution should be used when comparing decadal census data and the ACS. There are differences between the two: the decadal census data are not derived from sampled survey data, collection methods differ between the ACS and decadal census, and question response structure may differ.

Access Constraints:


More Information:

Suggested Citation for Data Displays:

Maine Center for Disease Control and Prevention, Maine Tracking Network. Lead Poisoning: Screening. Available online:  Accessed on [date accessed].