TheCompr

ehensi
veTestBanTr
eat
y(CTBT)

I
ntr
oduct
ion
The Compr ehensi
ve Test Ban Tr eat
y( CTBT) is a
multi
lat
eralagreementthatprohibi
tstheexplosivetest
ing
ofnuclearweapons.TheCTBTopenedf orsignatur
eson
September24,1996,butt he agreementisst il
lint he
rat
if
icati
onst age.TheUnitedStateshassi gned,buthas
notyetrati
fi
edt hetr
eat
y.

TheUni t
edSt atesconduct edthewor l
d’sf i
rstsuccessful
nuclearweaponst estonJul y16,1945.TheSov ietUnion
test
ed theirfir
stnucl earweapon on August29,1949.
These testsj ump-started a decades-long ar ms race
betweent het wo superpower s.Over2, 000 test
shav e
beendetectedonEar thorinEarth’sat
mospher e.

TheLi mi
tedTestBanTr eaty(1963),amul t
il
at eralt
reat
y
banning all nucl
ear t
est i
ng except f or under gr
ound
(at
mospher i
c,outerspace,and under water),and t he
Threshol
d TestBan Tr eaty( 1974),a bil
at eraltreat
y
between the Unit
ed States and Sov i
etUni on banning
nucl
eart
est
sof150ki
l
otonsormor
e(t
ent
imest
hesi
zeof

theHi r
oshimabombi ng),addressedconcernsaboutt he
safetyandenv i
ronment alimpactofnucleart esting,and
aimed to quellrisi
ng t ensi
ons between nucl ear-armed
states.The Compr ehensive Test Ban Tr eat yi st he
culminati
ngstepinbanni ngallexpl
osi
venucleart esting.

Oft heCTBT’s183si gnatories,164hav erati

fi
edt hetreat y
.
TheCTBTr equirest hatall44“ nucl
earcapabl e” st ates
(alsoknownas“ AnnexI I
”st at
es)rati
fythet r
eatybefor eit
mayent erintofor ce.EightAnnexI Istates hav ey ett o
ratif
ythe CTBT:t he Democr ati
c Peopl e’
s Republic of
Kor ea(Nort
hKor ea),India,and Pakistanhav e nei ther
signednorr ati
fi
ed,andt heUni t
edSt ates,China,Egy pt,
Ir
an,andI sraelhav esignedbuthav eyett o ratif
y.The
Uni t
edStat
esSenat efai
ledt orati
fytheCTBTi n1999wi th
av oteof51-48,butt helegislati
vebodycanst i
llrat
ifyt he
treatyi
nthefuture.

TheCompr ehensi
veTestBanTreat
yOr ganizat
ion(CTBTO)
Prepar
ator
yCommi ssi
on,
whichwascr eatedbythet reat
y
andensuresi t
spar ti
ali
mplementat
ion,hasest abli
shed
ver
ificati
onssystemsov erthelast20y earsto detect
nuclearexpl
osionsanywhereintheworl
d.Oncet hetr
eaty
entersintof
orce,theCTBTOwill
beoffi
cial
lyest
abli
shed.

Whatt
heTr
eat
yDoes

Zero-yi
eld:TheCTBT pr ohibit
sst at
esf rom exploding
nuclearmat erialregardl
essofwhet hert hepurposesar e
weapons- relatedorpeacef ul.Thet r
eatydoesnoti ncl
udea
technicalexpl anationofact i
vit
iesthatareallowedornot
all
owed,ef f
ect ivel
ybanningal lexplosiv
enucl earacti
vity
.
Thet reatybecomesl egall
ybi ndi
ngwheni tentersinto
force–whi chr equir
esal l44“ nucl
earcapabl e”stat
est o
signandr atifyt heagreement .

TheI nt ernati
onalMoni t
ori
ngSy stem (I
MS) :TheCTBT
establi
shes a gl obalsystem ofmoni tors designed to
detectnucl earexplosi
ons.TheCTBTO i sconf identthat
“t
heirsy st em candetectandident
ifyanymili
tari
l
yr el
evant
nucleart estany whereontheplanet.
”TheIMSi sexplained
i
ndet ailbel ow.
 Envir
onment alImpact:Theexpl osi vetestingofnucl ear
weaponsr eleasesr adi
oactivepar ticles(nucl ear fal
lout),
whichcausecel ldamagei nl i
v i
ngor ganisms.Whi l
et he
banonat mospher i
ct est
ingl imitedt heimpactofsome
short-
li
vedr adi
oactivemat erials,largeamount sofot her
harmful mat erial
s wer e r eleased under ground. The
rati
fi
cati
onoft heCTBTwoul dpr ovidel egalpr ot
ections
againstfur
therdamaget ot heenv ir
onmentandhumani t
y
bynucleartesti
ng.

The Compr ehensi

ve TestBan Tr eaty Or ganizat
ion
(CTBTO) :TheCTBTOPr eparat
oryCommi ssioni sbasedin
Vienna.Theor gani
zati
onpromot estheratif
icati
onoft he
treaty
,andimplementsthev er
if
icat
ionregime( seebelow)
sot hatitisfull
yoperati
onalwhent hetreatyent er
sinto
force.

Ver
if
icat
ion

TheI
nter
nat
ionalMoni
tor
ingSy
stem

TheI
MSf
eat
uresanet
wor
kof337moni
tor
ingf
aci
l
iti
es
andusesf ourtypesofmoni tor
ingmechani smst odetect
possiblenuclearexplosi
onsglobal
ly.Thedat acoll
ectedat
monitoringstati
onsi nvari
ouscountriesaroundthe world
i
ssentt otheI nternat
ionalDataCent eratt heCTBTO
PreparatoryCommi ssi
onheadquart
er sinVienna,whereit
i
spr ocessedandsentt omemberst ates.TheIMSi s90%
operati
onal t
oday .

Seismic:50pri
mar yand120auxi l
iar
ystati
onsdetect
shockwav esi
ntheearth.Thesestat
ionspri
maril
ypickup
data on eart
hquakes,butt hey al
so detectman-made
explosi
ons.

Hydroacoust
ic:11st
ati
onsdet
ectsoundwavesinthe
oceans.Thesoundwav esfr
om nucl
eardet
onat
ionscan
tr
aveldeepunderwater
.

Infrasound:Nucl
earexplosionsemitul
tr
a-l
owfr
equency
sound wav esthatarei naudibl
etot hehuman ear
.60
i
nfrasoundstati
onsdetectthesesoundwaves.

Radi
onucl
ide:80st
ati
onsdet
ectr
adi
oact
ivepar
ti
clesi
n
theatmosphere.40ofthesestat
ionsdetectnoblegases,
which can bett
erconf i
rm whethera det onati
on was
nuclear
.Ther
ear e16suppor
ti
veradionucl
idelabor
ator
ies.

On-
Sit
eInspect
ions

On-sit
ei nspecti
onsar econduct ed atther equestofa
StatePar t
yt otheCTBT.Ther equestmustbeappr oved
by30oft heExecut iveCouncil’
s51member s.Thepar ty
beinginspectedcannotr efuseaccesstoasuspect edsite.
The inspecti
on t eam mustar r
ive wit
hin sixday s ofa
requestbeingf i
led,andar eportissubmittedwi t
hin 25
daysoft herequest’sapproval
.