Hyphens, En Dashes, Em Dashes

Q. Where does Chicago stand on this “eco” compound word madness? Everything that comes across my desk these days is “eco-conscious, ecobusiness, eco centered,” and of course not a single word of it is consistent.

A. According to Merriam-Webster, eco- is a combining form rather than a prefix. In Chicago style, those are either hyphenated or closed depending on what the dictionary has (see CMOS 7.96, sec. 2, under “combining forms”). M-W lists “eco-conscious” (with a hyphen) but doesn’t list the other two, so you should hyphenate all three terms

[This answer relies on the 18th edition of CMOS (2024) unless otherwise noted.]