1.   After the fire investigators tested a similar oxygen canister to determine whether it could generate enough heat to cause the fire.

2.   The fire was caused by an electrical fault.

3.   The impact had mangled the plane but not caused a fire.

4.   We do not know what caused the fire and it is important for us to determine why.

5.   They have been theorizing about what may have caused the fire.

6.   The fire was caused by a short circuit.

7.   Forest fires are often caused by broken glass or by cigarette ends which people carelessly throw away.

8.   Farms are a soft target for arsonists, according to a report which says that up to a third of farm fires are caused deliberately.

9.   The spokesman said an investigation would begin today to find out what caused the fire.

10.   Among these are rules governing hazardous cargo, including materials that might cause fires.