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Study Information
Study Attribute Value
CEBS Accession Number: 002-01867-0001-0000-5
Chemical Name: Chloroform
CASRN: 67-66-3
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 564651_SCE
Study Result: Negative

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

Trial #: 1    Activation: No Activation    Date: 02/03/1987    Trial Call: Questionable   
  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 428 0.408 8.56 26.0 0.000
Test Chemical Chloroform 
160         
 50 1050 485 0.462 9.70 26.0 13.210 
500         
 50 1050 537 0.511 10.74 26.0 25.348 
1600         
 50 1051 471 0.448 9.42 26.0 9.837 
5000         
 50 1048 470 0.448 9.40 26.0 9.918
Positive Control Mitomycin-C 
 0.0E-4    
 50 1049 561 0.535 11.22 26.0 31.075
Mitomycin-C 
 0.005     
 10 210 297 1.414 29.70 26.0 246.632
Trend: 1.012        
Probability: 0.156        

Trial #: 2    Activation: No Activation    Date: 12/08/1987    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 1051 460 0.438 9.20 26.0 0.000
Test Chemical Chloroform 
50         
 50 1046 417 0.399 8.34 26.0 -8.914 
160         
 50 1046 398 0.380 7.96 26.0 -13.065 
500         
 50 1048 416 0.397 8.32 26.0 -9.306 
1600         
 50 1050 464 0.442 9.28 26.0 0.966
Positive Control Mitomycin-C 
 0.0E-4    
 50 1049 559 0.533 11.18 26.0 21.753
Mitomycin-C 
 0.005     
 10 210 261 1.243 26.10 26.0 183.966
Trend: 0.105        
Probability: 0.458        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 02/03/1987    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 1040 454 0.437 9.08 26.0 0.000
Test Chemical Chloroform 
160         
 50 1046 463 0.443 9.26 26.0 1.397 
500         
 50 1046 472 0.451 9.44 26.0 3.368 
1600         
 50 1043 470 0.451 9.40 26.0 3.226 
5000         
 50 1042 510 0.489 10.20 26.0 12.119
Positive Control Cyclophosphamide 
 0.1       
 50 1039 592 0.570 11.84 26.0 30.522
Cyclophosphamide 
 0.6       
 10 212 196 0.925 19.60 26.0 111.786
Trend: 1.722        
Probability: 0.043