Toxic, Damaging Precipitation
Puzzle 5 of Safety First Hard Pack
Question is: Toxic, Damaging Precipitation
and the answer is: ACIDRAIN
Word Meaning:
ACID RAIN — Rain which is unusually acidic (pH of less than the natural range of 5 to 6); caused mainly by atmospheric pollution with sulphur dioxide, carbon dioxide and nitrogen compounds.
Definitions from Wiktionary.