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Study Information
Study Attribute Value
CEBS Accession Number: 002-01232-0004-0000-4
Chemical Name: 2,4-Toluene diisocyanate
CASRN: 584-84-9
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 445615
Study Result: Positive


Table Instructions and Notes:
Studies are indicated to be "Nontoxic" when the observed reductions in relative total growth did not indicate that the maximum tolerated dose was achieved.

Nonactivation Trial: 1 Experiment Call: Inconclusive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 64 94 59 31 26
    71 99 65 31
    73 102 39 18
    71 104 49 23
Test Chemical 2,4-Toluene diisocyanate 
6.25      
 76 108 75 33 30
    76 103 63 28
  
12.5       
 87 81 46 18 21
    73 78 54 25
  
25         
 95 94 79 28 26
    77 86 56 24
  
50         
 80 59 59 24 27
    100 49 88 29
  
100         
 85 42 66 26 26
    80 42 63 26
  
200         
  
400         
   
Positive Control Methyl Methane Sulfonate 
15         
 24 17 123 174 148*
    30 19 109 122

Nonactivation Trial: 2 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 94 107 84 30 26
    92 94 72 26
    106 104 58 18
    98 95 85 29
Test Chemical 2,4-Toluene diisocyanate 
50         
 85 72 91 36 30
    91 72 68 25
  
75         
 80 55 39 16 22
    79 61 64 27
  
100         
 112 41 66 20 18
    89 34 43 16
  
125         
 79 30 59 25 26
    68 31 53 26
  
150         
 63 7 124 65 79*
    56 7 155 92
Positive Control Methyl Methane Sulfonate 
15         
 62 38 169 91 112*
    54 32 214 133

Induced S9 Trial: 1 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 71 102 137 64 53
    70 98 118 56
    76 90 100 44
    81 110 121 50
Test Chemical 2,4-Toluene diisocyanate 
50         
 78 91 110 47 44
    73 100 89 40
  
75         
 81 47 155 64 64
    82 37 158 65
  
100         
 76 30 136 59 67
    79 31 178 75
  
125         
 73 27 205 93 82
    65 18 139 71
  
150         
 66 20 207 105 121*
    39 10 162 138
Positive Control 3-Methylcholanthrene 
2.5       
 54 31 698 428 437*
    52 22 702 446

Induced S9 Trial: 2 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 68 98 68 33 26
    72 102 65 30
    74 102 36 16
    66 98 45 23
Test Chemical 2,4-Toluene diisocyanate 
50         
 56 47 52 31 38
    58 52 77 44
  
75         
 45 25 76 56 61*
    55 38 109 66
  
100         
 35 14 92 87 80*
    47 18 103 73
  
125         
 53 29 86 54 77*
    50 14 149 99
  
150         
 36 5 110 101 131*
    30 4 147 162
Positive Control 3-Methylcholanthrene 
2.5       
 34 26 193 192 210*
    36 21 246 228

Footnotes:
Asterisks(*) indicate significant responses.
r = rejected value due to quality control criteria
# = reduced sample size because of the loss of one culture dish due to contamination