An investigation by police and the FBI in Seattle, Wash., has disproved reports of a possible nerve gas attack against downtown Seattle at the end April, The Seattle Times reported April 11. Seattle Police Chief Gil Kerlikowske reportedly said authorities had seriously investigated the threat — from an unnamed group — even though it was based on weak information. The threat purportedly involved the use of the deadly nerve agent VX, which has the consistency of motor oil and works by causing all of the involuntary muscles in the body to contract. VX is regarded as the deadliest nerve agent created to date; as little as 10 milligrams is enough to kill an average person. The nature of VX, however, makes it difficult to disseminate over a large area, meaning it is one of the least effective agents to use in an attack aimed at causing mass casualties — hence, the agent has been used primarily for attempts against individual targets. Japanese doomsday cult Aum Shinrikyo, the group responsible for the most notorious use of nerve agents in an attack, released sarin nerve gas in the Tokyo subway system in 1995, killing 12 people and injuring thousands more. For a variety of reasons — primarily, an inadequate delivery system for the gas — the attack killed relatively few people, though a more successful attack could have been disastrous. Using modern laboratories and production facilities, the cult also synthesized a crude form of VX, using it to attack five people — including lawyers who were suing the cult, people suspected of spying and leaders of rival cults — between autumn 1994 and early 1995. According to testimony in a trial of Aum Shinrikyo leaders, the cult also reportedly killed 20 dissident members using VX in the fall of 1994. However, the VX produced by Aum Shinrikyo was not as potent — and therefore not as lethal — as the military-grade agent. Of the attempts on five of the group's enemies, only one person died, because the agent was directly injected into the victim. In the killings of the 20 dissident cult members, the VX was applied directly to the victims' skin. Attacks in which Aum Shinrikyo applied VX indirectly — to a target's door knob, a car door handle or in a ventilation system, for example — failed. Japanese police raided Aum Shinrikyo's facilities after the subway attacks, shutting down those operations. The CIA now reports, however, that al Qaeda has the ability to produce a crude form of VX. With very few exceptions, little can be done to protect against attacks with nerve agents, especially if an individual is targeted. Personal protection details for government officials and corporate executives routinely check for things such as bombs and listening devices, but not for nerve agents. The reason for this is that the cumbersome equipment needed for such a task — "sniffers" and test strips that can identify the presence of VX and other agents — must be operated by a team of specially trained technicians.