We would not recommend planting in the soil that was flooded by Hurricane Sandy. Have your soil tested. Petroleum products would need some serious treatment or removal. Adding compost to the existing soil will help bind up any heavy metals which may also be of concern. The bacteria from sewage should not be an issue after about 6 months. Raised beds with new soil would be an option. Refer any specific questions to health authorities or your county Extension agent. Useful links…
Brooklyn College: http://www.brooklyn.cuny.edu/web/academics/centers/esac/services/soil.php
Cornell: http://cnal.cals.cornell.edu/ | Learn more at Cornell University Cooperative Extension New York City
UMass : http://soiltest.umass.edu/
And there is some information on the Cornell Facebook page
Read this article from Cornell University: Are flooded veggies safe? Probably not.