An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Dales R, Wheeler A, Mahmud M, Frescura AM, Smith-Doiron M, Nethery E, Liu L.Dales R, et al.Environ Health Perspect. 2008 Oct;116(10):1423-7. doi: 10.1289/ehp.10943. Epub 2008 Aug 1.Environ Health Perspect. 2008.PMID: 18941589Free PMC article.