<Table> <Tr> <Th> NFPA 704 fire diamond </Th> </Tr> <Tr> <Td> 0 OX </Td> </Tr> <Tr> <Td> Fire diamond hazard sign for gaseous chlorine </Td> </Tr> </Table> <Tr> <Th> NFPA 704 fire diamond </Th> </Tr> <Tr> <Td> 0 OX </Td> </Tr> <Tr> <Td> Fire diamond hazard sign for gaseous chlorine </Td> </Tr>

What is the point at which toxicity first appears