How many letters does the top answer for “a fluorocarbon emitted as a by-product of industrial manufacturing” have?

The most common answer is hfc (3 letters).

Crossword clue: a fluorocarbon emitted as a by-product of industrial manufacturing

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

hfc 3 letters wn-def

a fluorocarbon emitted as a by-product of industrial manufacturing

hydrofluorocarbon 17 letters wn-def

a fluorocarbon emitted as a by-product of industrial manufacturing