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Study Information
Study Attribute Value
CEBS Accession Number: 002-01867-0002-0000-6
Chemical Name: Chloroform
CASRN: 67-66-3
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 564651_CA
Study Result: Equivocal

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

Trial #:1   Activation: No Activation    Date: 02/18/1987    Harvest Time: 12 hour(s)   Trial Call: Negative   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Dimethyl Sulfoxide 
0         
 200 1 0.005 0.5 0 0.000 0.0 1 0.005 0.5 0 0.000 0.0
Test Chemical: Chloroform 
500         
 200 1 0.005 0.5 1 0.005 0.5 0 0.000 0.0 0 0.000 0.0 
1000         
 200 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 
1600         
 200 2 0.010 1.0 0 0.000 0.0 2 0.010 1.0 0 0.000 0.0
Positive Control: Mitomycin-C 
 0.0625    
 200 36 0.180 17.0 13 0.065 6.5 22 0.110 10.5 1 0.005 1.0
Mitomycin-C 
 0.25      
 50 15 0.300 18.0 8 0.160 10.0 7 0.140 10.0 0 0.000 0.0
Trend: 0.355 -0.480 0.687  
Probability: 0.361 0.684 0.246  


Trial #:1_S9   Activation: Induced Rat Liver S9    Date: 02/18/1987    Harvest Time: 13 hour(s)   Trial Call: Weakly Positive   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Dimethyl Sulfoxide 
0         
 200 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Test Chemical: Chloroform 
1600         
 200 1 0.005 0.5 1 0.005 0.5 0 0.000 0.0 0 0.000 0.0 
3000         
 200 1 0.005 0.5 0 0.000 0.0 1 0.005 0.5 0 0.000 0.0 
5000         
 200 7 0.035 3.5 1 0.005 0.5 6 0.030 3.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
2.5       
 200 34 0.170 16.0 12 0.060 5.5 21 0.105 10.5 1 0.005 1.0
Cyclophosphamide 
7.5       
 50 21 0.420 22.0 2 0.040 2.0 9 0.180 18.0 10 0.200 1.0
Trend: 3.075 0.594 3.164  
Probability: 0.001 0.276 0.001  


Trial #:2_S9   Activation: Induced Rat Liver S9    Date: 01/19/1988    Harvest Time: 13 hour(s)   Trial Call: Questionable   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Negative (Not Specified) 
0         
 200 1 0.005 0.5 0 0.000 0.0 1 0.005 0.5 0 0.000 0.0
Test Chemical: Chloroform 
1600         
 200 7 0.035 3.5 2 0.010 1.0 5 0.025 2.5 0 0.000 0.0 
3000         
 200 4 0.020 2.0 1 0.005 0.5 3 0.015 1.5 0 0.000 0.0 
5000         
 200 3 0.015 1.0 0 0.000 0.0 3 0.015 1.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
2.5       
 200 28 0.140 12.0 3 0.015 1.5 25 0.125 11.0 0 0.000 0.0
Cyclophosphamide 
7.5       
 50 17 0.340 34.0 3 0.060 6.0 14 0.280 28.0 0 0.000 0.0
Trend: 0.012 -0.243 0.141  
Probability: 0.495 0.596 0.444