Consider the following statements regarding the principles of aseptic technique practiced in operating room :

1. All material that enters the sterile field must be sterile

2. The parts of gown worn by surgical team considered sterile are the front from chest to table level and sleeves up to 2 inches above elbow

3. A wide margin of safety is maintained between sterile and unsterile field

4. Tables are sterile at table top and up to 4 inches below it

Which of the statements given above is/are NOT correct?