For many years this 3-step approach has been used to reduce radiation exposure in HazMat incidents. This 3-step approach is also effective in handling EMS incidents.
Time: adequate time should be taken with a patient to ensure the highest standard of care is being administered, and when the job is done its time to go
Distance: onlookers and other people not treating an incident should be kept a significant distance from the scene
This is a simple, but very effective approach.