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Study Information
Study Attribute Value
CEBS Accession Number: 002-01015-0020-0000-1
Chemical Name: 1,1,1-Trichloroethane
CASRN: 71-55-6
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 247192
Study Result: Negative


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: Negative
  Conc.
uL/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 74 100 179 80 74
    70 82 185 88
    73 98 141 64
    76 120 143 63
Test Chemical 1,1,1-Trichloroethane 
 0.26      
 62 66 90 48 51
    56 54 91 54
  
 0.33      
 94# 72 81 29 30
    92 75 83 30
  
 0.41      
 89# 95 54 20
  
 0.51      
 65 18 77 40 33
    91# 16 70.5 26
  
 0.64      
   
Positive Control Ethyl Methane Sulfonate 
500         
 29 26 657 751 751*
    29# 24 772.5 883
    47 44 865 618

Nonactivation Trial: 2 Experiment Call: Negative
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 87 115 67 26 28
    83 85 76 30
Test Chemical 1,1,1-Trichloroethane 
 0.21      
 67 56 102 51 41
    48 42 44 30
  
 0.26      
 47 48 35 25 29
    82 70 82 33
  
 0.33      
 83 75 71 29 35
    46 41 57 41
  
 0.41      
 68 53 77 38 28
    67 53 36 18
  
 0.51      
 83 44 76 30
    126r 71 130 34
  
 0.64      
    91# 45 80 29
  
 0.8       
   
Positive Control Ethyl Methane Sulfonate 
500         
 50 40 995 668 542*
    49 30 975 663
    60 49 534 296

Nonactivation Trial: 3 Experiment Call: Negative
  Conc.
uL/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 62 102 49 26 28
    62 98 64 34
    56 92 60 36
    64 108 33 17
Test Chemical 1,1,1-Trichloroethane 
 0.21      
 56 56 42 25 24
    59 58 43 24
    74 111 52 23
  
 0.26      
 62 76 40 22 22
    63 82 52 28
    67 89 35 17
  
 0.33      
 61 60 72 39 27
    68 79 41 20
    62 72 39 21
  
 0.41      
 57 52 49 29 35
    62 44 62 33
    59 47 75 42
  
 0.51      
 68 41 59 29 23
    76 49 47 21
    39 19 22 19
  
 0.64      
   
   
Positive Control Ethyl Methane Sulfonate 
500         
 41 46 720 585 558*
    37 47 659 588
    43 48 649 501

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         
 63 102 227 120 119
    63 95 218 116
    65 108 208 106
    58# 95 232.5 134
Test Chemical 1,1,1-Trichloroethane 
 0.21      
 72 73 207 97 88
    67 86 160 80
  
 0.26      
 86 90 221 85 93
    66 71 199 101
  
 0.33      
 66 62 197 100 95
    78 64 211 91
  
 0.41      
 63 43 214 113 107
    62 45 189 101
  
 0.51      
 41 8 160 130 123
    46 12 158 116
  
 0.64      
   
Positive Control 3-Methylcholanthrene 
5         
 34 32 470 465 452*
    44# 28 451.5 345
    32 30 516 546

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         
 79 96 109 46 57
    91 110 154 57
    73 94 146 67
Test Chemical 1,1,1-Trichloroethane 
 0.21      
 61 72 68 37 38
    91 89 105 38
  
 0.26      
 77 68 127 55 37
    94 83 54 19
  
 0.33      
 124r 104 183 49
    113 93 185 54
  
 0.41      
 71 54 74 35 41
    62 54 86 46
  
 0.51      
 68 56 153 75 71
    80 49 159 67
  
 0.64      
 77 23 210 91 106*
    65 15 236 120
Positive Control 3-Methylcholanthrene 
5         
 35 19 395 382 349*
    36 21 362 340
    34 20 327 325

Induced S9 Trial: 3 Experiment Call: Negative
  Conc.
uL/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 75 96 83 37 41
    88 103 116 44
    72 93 73 34
    93 108 135 48
Test Chemical 1,1,1-Trichloroethane 
 0.21      
 60 59 75 42 37
    65 66 55 28
    77 79 99 43
  
 0.26      
 70 67 93 44 37
    66 57 52 26
    66 61 81 41
  
 0.33      
 61 51 42 23 35
    66 52 83 42
    74 63 89 40
  
 0.41      
 77 53 83 36 35
    68 50 43 21
    56 35 79 47
  
 0.51      
 58 21 62 35 45
    62 31 101 55
    67 27 92 46
  
 0.64      
   
   
Positive Control 3-Methylcholanthrene 
5         
 43 35 405 316 291*
    43 33 356 279
    50 39 413 276

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