BALTIMORE (AP) — Maryland environmental officials have invalidated seven lead-free certificates issued by a private inspector after finding issues with reports and tests.

The Maryland Department of the Environment said in a news release Thursday that is investigating whether rental properties certified by the inspector as having no lead paint are really free of the material.

Residents and owners of 384 Maryland properties certified lead-free by the private inspection contractor between 2010 and 2014 are being notified. Residents are being asked to complete an online on the condition of paint in the home.

Most properties are in Prince George’s County, officials say, with others in Anne Arundel, Baltimore, Calvert, Charles, Howard, Montgomery and St. Mary’s counties and Baltimore City.

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