The most common and most likely answer to this crossword clue is the 5 letter word FREON
F
R
E
O
N
Buddy explains!
The straight part
We know that "ozone-damaging gas" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ozone-damaging gas = freon.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does FREON mean?
FREON noun- Any of several non-flammable refrigerants based on halogenated hydrocarbon including R-12, R-22, and R-23.
- (refrigeration) A gaseous ozone-depleting refrigerant
- (environmentalism) A chlorofluorocarbon