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Study Information
Study Attribute Value
CEBS Accession Number: 002-01212-0001-0000-9
Chemical Name: 2,4- & 2,6-Toluene diisocyanate
CASRN: 26471-62-5
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 161856_SCE
Study Result: Weakly Positive

Study Result: Weakly Positive
Activation Trial Trial Call
No Activation  1  Weakly Positive 
No Activation  2  Weakly Positive 
Induced Rat Liver S9  1_S9  Negative 

Trial #: 1    Activation: No Activation    Date: 09/16/1986    Trial Call: Weakly Positive   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Dimethyl Sulfoxide 
0         
 50 1050 415 0.395 8.30 26.0 0.000
Test Chemical 2,4- & 2,6-Toluene diisocyanate 
16         
 50 1046 418 0.400 8.36 26.0 1.108 
50         
 50 1050 416 0.396 8.32 26.0 0.241 
160         
 50 1050 484 0.461 9.68 26.0 16.627 
500         
 50 1050 514 0.490 10.28 26.0 23.855 
1600         
 0 0 0 0.000 0.00 0.0 N/A
Positive Control Mitomycin-C 
 0.0E-4    
 50 1046 536 0.512 10.72 26.0 29.651
Mitomycin-C 
 0.005     
 10 210 329 1.567 32.90 26.0 296.386
Trend: 3.915        
Probability: 0.000        

Trial #: 2    Activation: No Activation    Date: 10/15/1986    Trial Call: Weakly Positive   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Dimethyl Sulfoxide 
0         
 50 1049 438 0.418 8.76 26.5 0.000
Test Chemical 2,4- & 2,6-Toluene diisocyanate 
100         
 50 1050 513 0.489 10.26 26.5 17.012 
160         
 50 1050 519 0.494 10.38 26.5 18.380 
300         
 50 1047 471 0.450 9.42 26.5 7.740 
500         
 50 1050 531 0.506 10.62 26.5 21.117
Positive Control Mitomycin-C 
 0.0E-4    
 50 1050 567 0.540 11.34 26.5 29.329
Mitomycin-C 
 0.005     
 10 209 339 1.622 33.90 26.5 288.468
Trend: 1.986        
Probability: 0.024        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 09/16/1986    Trial Call: Negative   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Dimethyl Sulfoxide 
0         
 50 1048 473 0.451 9.46 26.0 0.000
Test Chemical 2,4- & 2,6-Toluene diisocyanate 
5         
 50 1049 456 0.435 9.12 26.0 -3.686 
16         
 50 1050 450 0.429 9.00 26.0 -5.044 
50         
 50 1049 407 0.388 8.14 26.0 -14.036 
160         
 50 1050 475 0.452 9.50 26.0 0.232
Positive Control Cyclophosphamide 
 0.1       
 50 1047 568 0.543 11.36 26.0 20.199
Cyclophosphamide 
 0.6       
 10 210 256 1.219 25.60 26.0 170.098
Trend: -0.691        
Probability: 0.755