What is considered a chemical mutagen?

Chemical mutagen is a mutation agent which is in the form of chemical substance, It can mimic nitrogen base in normal DNA' but they cannot couple during DNA replication

A chemical mutagen isn't energy waves, chemical mutagens are actual chemicals.

Explanation:

Examples of chemical mutagens would be nicotine and other compounds in cigarette smoke that cause mutations involved in lung cancer. Or organic compounds containing 5 or 6 carbon planar ring structures that intercalate (i. e., get stuck between) the bases in DNA and cause errors in DNA replication and error checking mechanisms.