[HitmanLV]

[Hackett] said the strength of the bomb would be equivalent to “about four pounds of TNT. It doesn’t sound like much,” he allowed, “but it’s enough to kill everyone in the gallery.”

He's right - that doesn't sound like much. :-)

[burzum]

4 lbs of TNT is a lot of explosive. Each of the London bombings used 10 lbs of a stabilized form of acetone peroxide which has about the same explosive power as TNT. 4 lbs of TNT could certainly hurt many people.