1.   Thick smoke and dangerous levels of carbon monoxide prevented rescuers from reaching trapped men.

2.   A raging fire prevented rescuers from reaching some of the broken, twisted cars until hours after the crash.

3.   Blizzard conditions prevented rescuers from dropping supplies such as food and blankets overnight, when temperatures dipped into the low teens.

4.   Blocked roads prevented rescuers from responding to calls for help, and the upscale Conquistador Resort which overlooks the sea in Fajardo sustained extensive damage.

5.   But heavy mist and tropical storms over the past week had prevented rescuers from seeing anything, Zul said.

6.   But the director of the committee, Sheik Jaber al-Hakmi, denied his people prevented rescuers from entering the school.

7.   But the slabs of concrete braced with steel reinforcing bars that have saved her also prevent rescuers from reaching her.

8.   Continuing explosions and thick smoke prevented rescuers from reaching many of the damaged homes.

9.   Da Silva said the area smelled of gas from ruptured cans of cooking gas, preventing rescuers from using their kerosene lanterns for fear of an explosion.