While liquid explosives usually don't deliver the high-intensity blast of solid explosives, they still can cause a great deal of damage, according to chemists.
The amount of damage from a liquid-based bomb to an airliner would depend on the placement.
Chemistry professors at the University of Utah and Weber State University commented after reports Thursday that British authorities had arrested terror suspects who are believed to have planned to blow up aircraft flying from London to the United States.
"The terrorists planned to carry the components of the bombs, including liquid explosive ingredients and detonating devices disguised as beverages, electronic devices or other common objects," Michael Chertoff, secretary of the Department of Homeland Security, said in written remarks.
The discovery of their plan led to the immediate prohibition of most liquids and electronic devices from carry-on luggage at airports across the United States and Britain.
"There are many different types of liquid explosives," said Chuck Wight, a U. chemistry professor. "Some of them certainly involve mixtures of liquids which are oxidizers and other liquids which are fuels.
"And if you mix an oxidizer with a fuel, then you have an explosive. Most of them need a spark or some kind of impact to set them off."
The material is dangerous, sometimes going off on its own.
It is possible to create a high-energy liquid explosive, but none is as powerful as solid explosives used in military applications, he said. Even so, "they would still be able to detonate and still be able to do a lot of damage."
Some do not need to be mixed, he added, but most start with oxidizer and fuel, which are then combined.
Could a terrorist make the mixture before entering an airplane? "Certainly you could mix them ahead of time, but it would be very dangerous, and I think they would risk having the explosive go off before it was intended," Wight said.
A spark is not necessary to detonate some liquid explosives. For example, nitroglycerin, a yellow oil, could be synthesized outside an aircraft and carried in, said Spencer Seager, chemistry professor at WSU in Ogden.
"It's very sensitive to shock. Even the slightest bit of shaking and so forth could set it off."
For that reason, it might not be the weapon of choice for terrorists, who would not want to be blown up while walking through an airport concourse. Also, some of the liquids could be clear, making them hard to detect in a water bottle.
Even common liquids can become extremely explosive under certain conditions. Liquid gasoline is flammable, and "wouldn't create a lot of explosive force" if burned in the liquid state.
But if it were to vaporize — for example, if a terrorist poured gasoline inside an aircraft cabin and waited for the vapor to fill the cabin — it could cause a deadly blast. A terrorist, said Seager, possibly could "fill the aircraft with vapor."
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