Expect secondary effects such as chemical or radiological. Be prepared to use the hazmat protocals you have devloped for industrial or transportation accidents. Remember this is a crime scene, disturb things as little as possible and sill do your job. Destroyed buildings are very unstable, be careful. Recovery teathers and safety lines are good things.
Some targets have pre-existing hazards like chemical plants and biological labratories.
Rotate EMS personel. Tired people make bad mistakes. In a concerted terrorist campain EMS personel should expect to become primary targets themselves. Understand that it is unlikely that you will have either the proper training or equipment to do the job correctly. You are the canaries because FEMA and the other experts will not be able to get there until the situation is either safe or until your crew is already dying.