At what time did the Columbia crash?

How do you stop the machine in both normal and emergency situations and what is the procedure for restarting after an emergency? What is the medical term meaning emergency procedure to gain access below a blocked airway? What should be done if you come across a potential hazard and safety risk? What are the household use of acid-base indicator? Did people die during the twin tower collapse? When the swine flu hits what do you think the percentage of innocent people die because the virus will attach itself to a weaker immune system? Safety in the moment of ignorance? What will happen if the safety rules are not followed? What is the disaster management in a role of a citizen? How many people died in kedarnath flood? What is slow response to exceptional situation? Is an isolated tornado dangerous? What could happen if a hazard is left unattended? What are the effects of cloudbursts? How do you secure an outward opening door? What do you mean by pre monsoon? What year did the first wave of evacuation start? Setting of a shocking accident? Is an accidental fire covered by homeowners insurance? What time of the day is most dangerous for tornadic activity?