<P> Aquatic toxicity testing subjects key indicator species of fish or crustacea to certain concentrations of a substance in their environment to determine the lethality level . Fish are exposed for 96 hours while crustacea are exposed for 48 hours . While GHS does not define toxicity past 100 mg / l, the EPA currently lists aquatic toxicity as "practically non-toxic" in concentrations greater than 100 ppm . </P> <Table> <Tr> <Th> Exposure </Th> <Th> Category 1 </Th> <Th> Category 2 </Th> <Th> Category 3 </Th> </Tr> <Tr> <Td> Acute </Td> <Td> ≤ 1.0 mg / L </Td> <Td> ≤ 10 mg / L </Td> <Td> ≤ 100 mg / L </Td> </Tr> <Tr> <Td> Chronic </Td> <Td> ≤ 1.0 mg / L </Td> <Td> ≤ 10 mg / L </Td> <Td> ≤ 100 mg / L </Td> </Tr> </Table> <Tr> <Th> Exposure </Th> <Th> Category 1 </Th> <Th> Category 2 </Th> <Th> Category 3 </Th> </Tr> <Tr> <Td> Acute </Td> <Td> ≤ 1.0 mg / L </Td> <Td> ≤ 10 mg / L </Td> <Td> ≤ 100 mg / L </Td> </Tr>

The amount of toxin that an animal is exposed to