An analysis of state records found more than 1,800 schools across New York State that have never been tested for radon, including more than 400 schools in areas designated by the E.P.A. to have a high potential for elevated levels of the naturally-occurring gas.
New York's regulations include no requirement that school districts test buildings for radon. Applicants for a day care license must test for radon unless the day care is located in a public school. The newspaper analyzed nearly 70,000 pages of state records to create its own database and a map showing readers which school buildings have been tested, and which have not.