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.
Ou LT, Nkedi-Kizza P, Cisar JL, Snyder GH.Ou LT, et al.J Environ Sci Health B. 1992 Oct;27(5):545-64. doi: 10.1080/03601239209372800.J Environ Sci Health B. 1992.PMID: 1401729