A school nurse is notified of an emergency in which several children were injured following the collapse of playground equipment. Upon arrival at the playground, which of the following actions should the nurse take first?

A. Instructing a staff member to maintain a log of emergency care provided is not the first action that the nurse should take. This is an important task, but it can be done later, after ensuring the safety of the staff and children and providing immediate care to those who need it. 

B. Applying cervical spine collars to children who have suspected neck trauma is not the first action that the nurse should take. This is a priority intervention, but it can only be done after surveying the scene for potential hazards and making sure that it is safe to approach and touch the children. 

C. Notifying guardians of the emergency and injuries to their children is not the first action that the nurse should take. This is a necessary step, but it can be delegated to another staff member or done after providing initial care to the children. 

D. Surveying the scene for potential hazards to staff and children is the correct answer. This is the first action that the nurse should take, according to the principles of emergency care. The nurse needs to assess the situation and ensure that there are no dangers such as fire, electricity, gas, or falling debris that could harm anyone at the scene. The nurse also needs to determine how many children are injured, how severe their injuries are, and what resources are available to help them.