3-Quinuclidinyl benzilate

Did You Know?

• Antidotes for BZ include 7-MEOTA, atropine, and tacrine (THA).
• Physostigmine can temporarily increase synaptic acetylcholine concentrations to counter BZ effects.
• A 2022 documentary, Dr Delirium and The Edgewood Experiments, featured an interview with retired Army psychiatrist James Ketchum.

Physicochemical characteristics

BZ is a white crystalline powder with a bitter taste, odorless and nonirritating. It is stable in most solvents, with a half-life of three to four weeks in moist air. It persists in soil and water and on surfaces. Structurally, it is an ester of benzilic acid joined to a quinuclidine unit and a hydroxy group.

Effects

After exposure, symptoms appear in 30 minutes to several hours. BZ blocks muscarinic acetylcholine receptors, causing anticholinergic toxidrome. This includes delirium with hallucinations, cognitive issues, and inability to do basic tasks. Physical effects like dilated pupils, fast heart rate, dry mouth, and high body temperature occur. Effects last about three days, with some symptoms lasting up to six weeks.

Toxicity

Based on over 500 reported cases of accidental atropine overdose and deliberate poisoning, the median lethal oral dose is estimated at about 450 mg. The safety margin for BZ is inconclusive due to lack of human data at higher dosages. Some researchers have estimated lethality at 0.5 to 3.0 mg/kg and an LD01 of 0.2 to 1.4 mg/kg.

History

Hoffman-LaRoche invented BZ in 1951 while investigating antispasmodic agents for gastrointestinal ailments. The United States military later investigated it as a nonlethal incapacitating agent. By 1959 the U.S. Army showed interest in deploying it, and it was standardized in 1961 under the NATO code BZ. It became known as 'Buzz' from its abbreviation and effects on volunteers at Edgewood Arsenal. Work in 1964 included Project DORK, a scheme to incapacitate a trawler with aerosolized BZ. It was weaponized in the M44 generator cluster and M43 cluster bomb; stocks were destroyed in 1989. Survivors of the 1995 Srebrenica massacre claimed attack with a chemical agent causing hallucinations. In 1998 the British Ministry of Defence accused Iraq of stockpiling Agent 15, likely identical to BZ, though the CIA later concluded Iraq had not stockpiled or weaponized it.