Is DNA green viewer carcinogenic?
SYBR green is designed to be much less carcinogenic than ethidium bromide (EtBr).  

All these gel dyes work by intercalating themselves into the DNA stack between the bases specifically which has a great potential for causing mutations and messing with the workings of the nucleus.  My remembrance is that the SYBR and GelGreen/Red etc dyes are large and relatively hydrophilic and can't find their way into the nucleus, greatly reducing their toxicity.  They also do not transfer energy to the DNA itself due to their structure and so also cause less DNA damage when being viewed on a transilluminator.