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Study Information
Study Attribute Value
CEBS Accession Number: 002-01015-0021-0000-2
Chemical Name: 1,1,1-Trichloroethane
CASRN: 71-55-6
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 920365
Study Result: Equivocal


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.
uL/mL
Cloning
Efficiency
Relative Total
Growth
Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide
 0         
97 100 41 14 21
    124r 133 57 15
    117# 123 87 25
    80 77 58 24
Test Chemical 1,1,1-Trichloroethane
 0.05      
67 65 30 15 18
    94 78 66 23
    110 110 47 14
 
 0.1       
93# 78 42 15 13
    106 100 34 11
    91# 102 40.5 15
 
 0.2       
114 98 51 15 14
    135r 92 73 18
    115 94 45 13
 
 0.4       
   
   
Positive Control Ethyl Methane Sulfonate
500         
23 6 727 1054 1084*
    27# 13 718.5 887
    11 4 413 1311

Nonactivation Trial: 2 Experiment Call: Negative and Non-Toxic
  Conc.
uL/mL
Cloning
Efficiency
Relative Total
Growth
Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide
 0         
85# 86 57 22 22
    85 102 64 25
    93 111 49 18
Test Chemical 1,1,1-Trichloroethane
 0.05      
79 90 63 27 24
    82 91 53 22
    81 88 60 25
 
 0.1       
70 81 41 19 28
    69# 86 82 40
    63# 68 49.5 26
 
 0.2       
75 86 59 26 30
    80# 71 81 34
 
 0.4       
81 81 56 23 26
    84 69 75 30
 
 0.5       
70# 69 51 24 26
    75 16 63 28
    81 69 75 31
    89 80 58 22
Positive Control Ethyl Methane Sulfonate
500         
11 5 393 1156 1156*
    8r 2 360 1440
    5r 1 348 2320

Nonactivation Trial: 3 Experiment Call: No Call
  Conc.
uL/mL
Cloning
Efficiency
Relative Total
Growth
Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide
 0         
127r 124 83 22 34
    118 116 101 28
    88 92 89 34
    76 91 91 40
Test Chemical 1,1,1-Trichloroethane
 0.05      
60 78 37 20 22
    94 55 68 24
 
 0.1       
72# 61 31 14 24
    75 60 67 30
    53 60 42 26
 
 0.2       
122r 81 40 11 17
    83 59 55 22
    90 87 33 12
Positive Control Ethyl Methane Sulfonate
500         
4r 1 168 1600
    4r 1 134 1218
    2r 0 125 1923

Nonactivation Trial: 4 Experiment Call: Negative
  Conc.
uL/mL
Cloning
Efficiency
Relative Total
Growth
Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide
 0         
112 110 114 34 26
    102# 87 78 26
    111 111 69 21
    95 92 63 22
Test Chemical 1,1,1-Trichloroethane
 0.05      
113 109 42 12 21
    117# 82 85 24
    108 99 88 27
 
 0.1       
97 81 57 20 19
    103 95 70 23
    99 97 42 14
 
 0.2       
109 68 87 27 24
    104 71 66 21
 
 0.4       
94# 47 52.5 19 28
    94 8 82 29
    112 6 120 36
 
 0.5       
   
   
Positive Control Ethyl Methane Sulfonate
250         
92 58 1115 404 375*
    81# 48 916.5 380
    94 51 961 341

Nonactivation Trial: 5 Experiment Call: Negative and Non-Toxic
  Conc.
uL/mL
Cloning
Efficiency
Relative Total
Growth
Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide
 0         
67 80 113 56 54
    64 116 105 55
    64 102 106 55
    69 102 100 49
Test Chemical 1,1,1-Trichloroethane
 0.05      
65 105 97 50 48
    57 93 83 49
    52 101 72 46
 
 0.1       
53 95 75 47 55
    42 75 86 69
    71# 105 105 49
 
 0.2       
72 91 161 75 59
    68 88 93 45
    54 82 93 58
 
 0.3       
66 75 104 52 52
    74 76 116 53
    86 92 134 52
 
 0.4       
53 55 96 60 60
    55 16 109 66
    59# 59 93 53
Positive Control Ethyl Methane Sulfonate
250         
32 25 721 751 788*
    25 19 692 941
    33# 40 670 672

Non-Induced S9 Trial: 1 Experiment Call: Rejected
  Conc.
uL/mL
Cloning
Efficiency
Relative Total
Growth
Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide
 0         
72 96 290 134 126
    73 88 260 118
    77 110 323 140
    80 106 273 114
Test Chemical 1,1,1-Trichloroethane
 0.05      
65 65 252 129 171
    34# 21 213 210
    55 32 285 173
 
 0.1       
39 25 241 206 172
    61 34 217 118
    49 30 281 191
 
 0.2       
57 30 322 189 189*
    68# 27 426 210
    66 35 331 166
 
 0.3       
68 35 365 179 225*
    47 27 343 245
    60 19 450 250
 
 0.4       
296*
    49 10 362 245
    48 15 497 346
 
 0.5       
   
   
Positive Control 3-Methylcholanthrene
3.5       
44 39 515 393 415*
    45 40 590 437
    45# 27 563 415

Induced S9 Trial: 1 Experiment Call: Positive
  Conc.
uL/mL
Cloning
Efficiency
Relative Total
Growth
Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide
 0         
92 105 100 36 38
    82 86 106 43
    103 109 108 35
Test Chemical 1,1,1-Trichloroethane
 0.0078    
91 56 91 33 44
    99 107 159 54
 
 0.0156    
102 111 154 50 57
    79 86 148 63
 
 0.0313    
88 73 176 66 62*
    102 99 176 58
 
 0.0625    
85 84 133 52 44
    96 120 102 36
 
 0.125     
106 75 133 42 49
    103 110 176 57
 
 0.25      
96 69 217 75 82*
    97 58 256 88
Positive Control 3-Methylcholanthrene
5         
419*
    21 2 211 343
    22 2 326 494

Induced S9 Trial: 2 Experiment Call: Positive
  Conc.
uL/mL
Cloning
Efficiency
Relative Total
Growth
Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide
 0         
93 93 167 60 49
    80 110 102 43
    95 87 134 47
    95 110 135 47
Test Chemical 1,1,1-Trichloroethane
 0.025     
87 75 241 92 68
    87 86 127 48
    100 96 193 65
 
 0.05      
95 71 149 52 59
    101 92 189 62
    89 90 168 63
 
 0.1       
118 92 224 63 69
    104 73 242 77
    98 78 196 66
 
 0.2       
99 73 219 74 83*
    84 58 244 97
    103 68 236 77
 
 0.3       
95 61 261 91 98*
    85 26 281 110
    84 17 232 92
 
 0.4       
62 11 263 141 104*
    64 7 181 94
    98 41 228 78
 
 0.5       
   
   
Positive Control 3-Methylcholanthrene
5         
23 3 231 342 371*
    27 4 282 350
    28 3 358 421

Induced S9 Trial: 3 Experiment Call: Negative and Non-Toxic
  Conc.
uL/mL
Cloning
Efficiency
Relative Total
Growth
Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide
 0         
99 107 121 41 38
    93 101 90 32
    106# 90 114 36
    90 102 111 41
Test Chemical 1,1,1-Trichloroethane
 0.05      
82 55 85 34 38
    66 74 83 42
    91 113 107 39
 
 0.1       
86 66 75 29 34
    74 76 91 41
    90 83 85 32
 
 0.2       
76 64 87 38 45
    88 82 138 52
    90 82 121 45
 
 0.3       
76 57 77 34 35
    65 64 82 42
    78 65 70 30
 
 0.4       
78 39 123 52 58*
    65 7 112 58
    82 60 156 63
 
 0.5       
75 23 146 65 55
    77 27 103 45
    65 8 111 57
Positive Control 3-Methylcholanthrene
5         
32 4 380 398 369*
    31 5 344 374
    35 6 349 334

Induced S9 Trial: 4 Experiment Call:
  Conc.
uL/mL
Cloning
Efficiency
Relative Total
Growth
Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide
 0         
86 102 100 39 33
    95 107 100 35
    89 101 70 26
    102# 90 92 30
Test Chemical 1,1,1-Trichloroethane
 0.05      
79 55 70 30 32
    87 113 84 32
    64 75 68 36
 
 0.1       
70 76 78 37 30
    86 83 71 28
    82 66 64 26
 
 0.2       
86 82 114 44 42
    70 61 75 36
    85 82 119 47
 
 0.3       
74 58 67 30 32
    64 66 70 37
    75 65 62 28
 
 0.4       
79 60 134 56 49
    76 40 98 43
    61 6 87 48
 
 0.5       
72 26 83 38 49*
    72 23 127 59
    62 8 92 49
Positive Control 3-Methylcholanthrene
5         
28 5 269 324 318*
    31 5 269 289
    29 4 298 341

Induced S9 Trial: 5 Experiment Call: Negative and Non-Toxic
  Conc.
uL/mL
Cloning
Efficiency
Relative Total
Growth
Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide
 0         
100 115 52 17 24
    104# 93 81 26
    98 105 69 23
    104# 86 85.5 28
Test Chemical 1,1,1-Trichloroethane
 0.1       
96 74 100 35 29
    95 95 64 23
    78 66 71 31
 
 0.2       
98# 78 99 34 31
    95 82 85 30
    94 65 85 30
Positive Control 3-Methylcholanthrene
2.5       
96 56 638 221 218*
    88# 56 592.5 225
    79 54 491 207

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