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: 002-01863-0011-0000-2
Chemical Name: Chlorobenzene
CASRN: 108-90-7
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 103069
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         
97 99 111 38 30
    97 92 103 36
    86 99 53 20
    111 110 88 27
Test Chemical Chlorobenzene
6.25      
97 99 113 39 43
    92 85 128 46
 
12.5       
88 94 78 30 34
    95 93 108 38
 
25         
81 69 78 32 34
    75 75 80 36
 
50         
80 66 82 34 34
    79 74 78 33
 
100         
64 52 66 34 33
    68 55 64 31
 
200         
   
Positive Control Methyl Methane Sulfonate
15         
29 19 242 278 261*
    32 18 236 243
Methyl Methane Sulfonate
250         
73 68 273 125 131*
    82 61 337 137

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         
80 90 100 42 41
    85 95 114 45
    91 108 129 47
    100 107 96 32
Test Chemical Chlorobenzene
50         
87 73 126 48 48
    79 66 112 47
 
75         
94 73 142 50 48
    99 57 133 45
 
100         
84 45 157 62 77*
    76 37 210 92
 
125         
70 22 393 188 178*
    68 23 342 169
 
150         
30 4 445 494 597*
    26 3 535 699
 
175         
   
Positive Control Methyl Methane Sulfonate
15         
45 20 218 161 176*
    42 22 240 191
Methyl Methane Sulfonate
250         
62 66 307 166 154*
    69 59 293 142

Nonactivation Trial: 3 Experiment Call: Positive
  Conc.
ug/mL
Cloning
Efficiency
Relative Total
Growth
Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide
 0         
83 97 52 21 27
    80 96 101 42
    78 94 65 28
    85 113 46 18
Test Chemical Chlorobenzene
40         
76 73 46 20 19
    78 95 41 18
 
70         
83 69 60 24 27
    73 67 67 31
 
100         
86 35 95 37 37
    72 44 79 37
 
130         
67 19 88 44 42
    56 14 68 40
 
160         
16 1 34 70 75*
    28 3 67 79
 
190         
 
220         
   
Positive Control Methyl Methane Sulfonate
20         
29 16 167 189 165*
    37 25 159 142
Methyl Methane Sulfonate
250         
65 71 399 204 223*
    74 64 542 243

Nonactivation Trial: 4 Experiment Call: Equivocal
  Conc.
ug/mL
Cloning
Efficiency
Relative Total
Growth
Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide
 0         
90 101 166 61 54
    60 98 95 53
    78 99 128 55
    62 102 86 47
Test Chemical Chlorobenzene
135         
45 29 86 64 64
    44 27 83 64
 
150         
37 22 81 72 71
    37 20 79 71
 
165         
47 16 92 66 58
    53 22 80 50
 
180         
39 7 70 60 83
    51 9 162 106
 
195         
14 1 95 226 197*
    22 2 110 168
Positive Control Methyl Methane Sulfonate
15         
25 19 156 212 195*
    25 18 135 178

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         
61 103 84 46 49
    67 95 87 43
    52 102 72 46
    55 101 101 61
Test Chemical Chlorobenzene
70         
49 22 181 124 112*
    54 29 160 99
 
100         
75 28 256 114 118*
    66 25 241 122
 
130         
57 26 153 90 103*
    62 31 218 117
 
160         
52 21 179 116 107*
    55 21 162 99
 
190         
35 15 100 95 114*
    30 11 121 134
Positive Control 3-Methylcholanthrene
2.5       
46 30 500 364 403*
    36 35 474 443

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         
70 109 113 54 64
    63 83 138 73
    72 98 84 39
    66 110 176 89
Test Chemical Chlorobenzene
70         
61 29 253 138 117*
    71 36 205 96
 
100         
50 22 148 98 104*
    54 35 180 110
 
130         
44 21 155 117 102*
    67 43 174 86
 
160         
41 14 219 179 161*
    45 16 193 143
 
190         
22 5 93 143 172*
    23 4 138 200
Positive Control 3-Methylcholanthrene
2.5       
31 20 572 622 517*
    26 17 327 411

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