Answer:

atest

Answer	Crossword Clue
ATEST	"This is only ....."
ATEST	Bomb try-out
ATEST	Blast from the past?

ATEST	Event in 37D
ATEST	"This is only ..."
ATEST	Alamogordo event
ATEST	Bikini event
ATEST	"This is ... of the emergency broadcast system ..."
ATEST	Bikini explosion
ATEST	Blast from the past
ATEST	"This is only ...."

ATEST	Nuclear experiment
ATEST	Bomb experiment
ATEST	"This is only .. "
ATEST	Blast with fallout
ATEST	"This is only .."
ATEST	Bomb blast, in headlines
ATEST	Explosion near Alamogordo
ATEST	Alamogordo experiment

ATEST	'40s Bikini trial
ATEST	'50s blast
ATEST	'50s nuclear trial
ATEST	Bikini blast
ATEST	Big blast
ATEST	Bikini activity
ATEST	"This is .."
ATEST	'50s nuclear blast

ATEST	Bikini trial
ATEST	Boomer experiment?
ATEST	'50s nuclear experiment
ATEST	'50s headline event
ATEST	Controversial explosion
ATEST	Old fallout source
ATEST	Operation Crossroads event, 1946
ATEST	Explosive experiment

ATEST	White Sands, N.M. event
ATEST	"This is only ...!" (radio message)
ATEST	"This is only ..." (part of an old TV message)
ATEST	Bikini atoll event
ATEST	Bikini blowout