Table 2.

Testing chemicals for the positive results in bacterial reverse mutation assay and the negative results in carcinogenicity studies^a

No.	Chemical Name	The Positive Results in Bacterial Reverse Mutation Assay				Carcinogenicity Studies
		Without S9	With S9	The Highest Specific Activityb and the Strain	Ref.		Ref.
1	4-(Chloroacetyl)-acetanilide	Neg	Pos	600 revertants/mg in TA1538 with S9	[18, 19]	Neg	[20]
2	2-(Chloromethyl) pyridine HCl	Pos	Pos	98.6 revertants/mg in TA100 with S9	[21]	Neg	[22]
3	2,6-Diaminotoluene	Neg	Pos	1703 revertants/mg in TA100 with S9	[23]	Neg	[24]
4	2,5-Diaminotoluene	Neg	Pos	8060 revertants/mg in TA98 and 3840 revertants/mg in TA100 with S9	[25]	Neg	[26]
5	HC Blue No.2	Pos	Pos	153.6 revertants/mg in TA98 with S9	[27, 28]	Neg	[29]
6	8-Hydroxyquinoline	Neg	Pos	21,400 revertants/mg in TA97 and 16,000 revertants/mg in TA100 with S9	[28]	Neg	[30]
7	Iodoform	Pos	Pos	465 revertants/mg in TA98 and 450 revertants/mg in TA100 with S9	[31]	Neg	[32]
8	4-Nitroanthranilic acid	Pos	Pos	3600 revertants/mg in TA1535 and 2830 revertants/mg in TA100 with S9	[33]	Neg	[34]
9	1-Nitronaphthalene	Pos	Pos	14,700 revertants/mg in TA100 without S9 and 12,500 revertants/mg in TA100 with S9	[35]	Neg	[36]
10	4-Nitro-o-phenylenediamine	Pos	Pos	41,400 revertants/mg in TA100 without S9	[37–40]	Neg	[41]

^aPos Positive, Neg Negative

^bSpecific activity value indicating that strong mutagenicity is observed in the Ames test is approximately 1000 (revertants / mg) or more, and to be calculated as below

Specific activity (revertants / mg) = {(Number of colonies per plate at the dose value) - (Number of colonies per plate in negative control test)}/The dose value (μg) X 1000