Filed from 4 published puzzles

EMISSION

Set to 4 different clues across 4 published puzzles, most often “E.P.A. measurement” — The New York Times, Saturday, 25 December 2010.

8 letters

Every clue on record, most used first

E.P.A. measurementonce
The New York Times — Saturday, 25 December 2010
Releaseonce
The New York Times — Saturday, 15 July 2006
Discharge into the aironce
The New York Times — Sunday, 5 February 2006
Dischargeonce
The New York Times — Tuesday, 26 October 1999

Other answers to these clues

EGEST5 letters
EMIT4 letters
EXEMPT6 letters
EXHALE6 letters
LETGO5 letters
LETOFF6 letters
SETFREE7 letters
UNDO4 letters
UNHAND6 letters
UNLOOSE7 letters
UNTIE5 letters