COVID-19 is an emerging, rapidly evolving situation.

Get the latest public health information from CDC and research information from NIH.

U.S. flag

An official website of the United States government

Dot gov

The .gov means it's official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Share This:
Study Information
Study Attribute Value
CEBS Accession Number: 002-01223-0001-0000-1
Chemical Name: 2,4-Dichlorophenoxyacetic acid
CASRN: 94-75-7
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 079515_SCE
Study Result: Positive

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

Trial #: 1    Activation: No Activation    Date: 02/26/1982    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         
25 513 203 0.396 8.12 25.5 0.000
Test Chemical 2,4-Dichlorophenoxyacetic acid
50         
50 1008 448 0.444 8.96 25.5 12.315
167         
50 1026 591 0.576 11.82 25.5 45.567
Positive Control Mitomycin-C
 0.005     
10 210 290 1.381 29.00 25.5 248.980
Trend: 5.210        
Probability: 0.000        

Trial #: 2    Activation: No Activation    Date: 03/03/1982    Trial Call: 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 1020 401 0.393 8.02 26.5 0.000
Test Chemical 2,4-Dichlorophenoxyacetic acid
198         
50 1029 625 0.607 12.50 32.1 54.497
248         
50 1026 646 0.630 12.92 32.1 60.155
299         
50 1022 668 0.654 13.36 32.1 66.258
352         
0 0 0 0.000 0.00 0.0 N/A
Positive Control Mitomycin-C
 0.005     
25 510 589 1.155 23.56 26.5 193.766
Trend: 7.545        
Probability: 0.000        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 02/26/1982    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 1039 477 0.459 9.54 25.5 0.000
Test Chemical 2,4-Dichlorophenoxyacetic acid
500         
50 1047 494 0.472 9.88 25.5 2.773
1670         
50 1045 497 0.476 9.94 25.5 3.595
5000         
0 0 0 0.000 0.00 25.5 N/A
Positive Control Cyclophosphamide
1.5       
25 515 688 1.336 27.52 25.5 190.990
Trend: 0.547        
Probability: 0.292        

Trial #: 2_S9    Activation: Induced Rat Liver S9    Date: 03/11/1982    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 1049 382 0.364 7.64 25.5 0.000
Test Chemical 2,4-Dichlorophenoxyacetic acid
3000         
50 1035 398 0.385 7.96 25.5 5.598
3500         
50 1019 393 0.386 7.86 25.5 5.908
4200         
50 1036 452 0.436 9.04 25.5 19.809
5000         
0 0 0 0.000 0.00 0.0 N/A
Positive Control Cyclophosphamide
1.5       
50 1045 1072 1.026 21.44 25.5 181.702
Trend: 2.538        
Probability: 0.006