Filed from 6 published puzzles

FLOOD

Set to 6 different clues across 6 published puzzles, most often “Reason for 21-Across” — The New York Times, Thursday, 17 December 2009.

5 letters

Every clue on record, most used first

Reason for 21-Acrossonce
The New York Times — Thursday, 17 December 2009
Overrunonce
The New York Times — Thursday, 17 March 2005
Johnstown disasteronce
The New York Times — Wednesday, 17 April 2002
Kind of insuranceonce
The New York Times — Thursday, 14 December 2000
Result of a bank failure?once
The New York Times — Monday, 17 March 1997
Subject of Genesis 7-8once
The New York Times — Friday, 13 January 1995

Other answers to these clues

CASUALTY8 letters
DELUGED7 letters
INFEST6 letters
INVADE6 letters
RIFE4 letters
SWARMINTO9 letters
TEEM4 letters