http://www.cpsc.gov/cpscpub/pubs/466.html
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U.S. Consumer Product Safety Commission
This page provides answers to questions about carbon monoxide (CO) is a colorless, odorless, poisonous gas. The page includes information on how many people are unintentionally poisoned by CO, what the symptoms of CO poisoning are, what one should you do to prevent CO poisoning, what CO level is dangerous to health, and more.