Matsumoto sarin attack

The Tokyo subway sarin attack occurred in 1995, following the Matsumoto sarin attack, and served as a wake-up call for anti-NBC (nuclear, biological, and chemical) terrorism policy throughout the world. In the 10 years since the attack, efforts to combat NBC terrorism have focused on rapid and effective measures to respond to attacks employing nerve agents such as sarin. 

Given the low concentration and means of dispersal, the Tokyo subway sarin attack can be referred to as a passive attack. The implication of such an assumption is therefore that mankind has not yet witnessed a full-scale sarin attack in any major city. While valuable information can certainly be gained from the Tokyo subway sarin attack, the experience obtained from the more aggressive Matsumoto sarin attack and the Iran-Iraq war should also be considered when developing initiatives directed at dealing with a potential full-scale attack in the future where the effects will be more serious. 

The alkyl methylphosphonic acids provide a convenient marker for determining exposure to nerve agents. Numerous modifications for the assay of these compounds have been developed for blood or urine, and several have been applied to actual human exposure cases. Important factors in considering this test are extent of exposure and time following the event. One of the most severely poisoned victims of the Matsumoto sarin attack demonstrated measurable IMPA in the urine on the seventh day. To put the severity of this case in perspective, AChE values were in the range of 5%-8% of normal (Nakajima et al., 1998). However, in most cases, hydrolysis products should not be considered to be present for more than 24-48 h following exposure. The methods used to verify human exposure to nerve agents based on assay of hydrolysis products are presented in Table 19.2. 

The Matsumoto sarin attack occurred on June 27, 1994, one year before the Tokyo subway sarin attack, and although the group responsible for the Matsumoto attack was not known at the time of the Tokyo subway attack, emergency doctors in Japan knew that the diagnosis and treatment of sarin poisoning should follow that of accidental organophosphorus poisoning. 

Dr Yanagisawa heads the Shinshu University Hospital where many of the victims of the Matsumoto sarin attack were treated. When he heard that several people had died in Tokyo and that many of the patients had miosis, he telephoned the St. Luke s International Hospital after 10 00 am to exchange information with emergency doctors at the hospital. The doctors reached the conclusion that the victims were probably suffering from sarin poisoning. In... 

Given the earlier Matsumoto sarin attack experience, sarin poisoning was diagnosed relatively smoothly based on the symptoms and laboratory findings (particularly assays of plasma cholinesterase). 

Thus, the way in which we use the lessons learned from this attack will affect our ability to deal adequately with future terrorist attacks using sarin, which could be even greater and more serious with respect to the number of victims. Can we really assume that only 12 of the approximately 5,500 victims died because the Japanese medical system was particularly well prepared for such an eventuality Probably not. It is more likely that the relatively small number of fatalities was due to the low concentration of sarin and the passive means of dispersing it. From tiiis perspective, the Matsumoto sarin attack one year earlier was more aggressive than the Tokyo subway sarin attack. In a trial after the Matsumoto incident, it was revealed tiiat a 70% concentration of sarin was actively volatilized using an electric heater and dispersed using an electric fan. A total of 7 victims died and 660 were injured and one victim died 14 years after sarin exposme. In other words, if the Tokyo subway sarin attack had been conducted using the same means as those employed in the Matsumoto sarin attack, the number of fatalities may have been 50 or 60. So humanity has not yet experienced the effects of a full-scale sarin attack in a major city. 

According to inpatient records from St Luke s Hospital, the most common laboratory finding related to sarin toxicity was a decrease in plasma cholinesterase (ChE) levels in 74% of patients. In patients with more severe toxicity, plasma ChE levels tended to be lower, but a more accurate indication of ChE inhibition is measurement of erythrocyte ChE, as erythrocyte ChE (AChE) is considered true ChE and plasma ChE is pseudo ChE . However, erythrocyte ChE is not routinely measured, whereas plasma ChE is included in many clinical chemistry panels thus, it can be used as a simple index for ChE activity. In both the Matsumoto and Tokyo subway sarin attacks, plasma ChE served as a useful index of sarin exposure. In 92% of hospitalized patients, plasma ChE levels returned to normal on the following day. In addition, inpatient records from... 

Miyaki, K., Nishiwaki, Y., Maekawa, K., Ogawa, Y., Asukai, N., Yoshimura, K., Etoh, N., Matsumoto, Y., Kikuchi, Y., Kumagai N., Omae, K. (2005). Effects of sarin on the nervous system of subway workers seven years after the Tokyo subway sarin attack. J. Occup. Health 47(4) 299-304. 

Distribution, metabolism, and elimination of sarin in humans appear to resemble findings in animals. Minami and colleagues (1997, 1998) detected the sarin metabolite IMPA in urine of humans after the terrorist attack in Tokyo in 1995. They found peak levels of IMPA or methylphosphonic acid in urine 10-18 h after exposure. The levels of IMPA in urine correlated with the clinical symptoms. They also found evidence of distribution of sarin to the human brain in four of the 12 people who died after exposure. IMPA and MPA were detected in patients from the Matsumoto sarin exposure (Nakajima et al, 1998). 

Sekijima, Y., Morita, H., Shindo, M., Okudera, H., Shibata, T., Yanagisawa, N. (1995). A case of severe sarin poisoning in the sarin attack at Matsumoto—One-year follow-up on the clinical findings and laboratory data. Rinsho Shinkeijaku, 35, 1241-1245. 

Security aspect. This review of AUM Shinrikyo s terrorist activity reveals a new threat to stability of democratic societies - chemical terrorism. Especially terrifying dimension of the problem is the fact that members of this fanatic cult used nerve gases three times against civilian population - sarin in Matsumoto and Tokyo in June, 1994 and in March, 1995, respectively, and VX in Tokyo in January, 1995. The two sarin attacks were especially dangerous, because they threatened the lives of hundreds of citizens. 

Spasm of the ciliary muscle may impair accommodation and is associated with severe headache. Long-lasting miosis, associated with eye pain, was a notable clinical sign in the Tokyo Subway (underground railway) terrorist attack with sarin and the same was true of the sarin attack at Matsumoto (Nohara and Segawa, 1996). 

The Matsumoto and Tokyo subway sarin attacks were wake-up calls to NBC terrorism. These incidents proved that terrorists could actually deploy chemical weapons and weapons of mass destruction. We have previously analyzed and reported on the Tokyo subway sarin attack from the viewpoint of clinical medicine (Okumura el al., 1996,1998a, 1999). Here, by including the findings of the court trials and information related to the attacks that has become available, we review the experiences and lessons learned from the Tokyo subway sarin attack in the hope that doing so will improve measures against chemical terrorism. 

In the Tokyo subway sarin attack, the amount of atropine sulfate administered was markedly smaller than what has been proposed in the past. The reason for this may be that the concentration of sarin used in the attack was low, at 35%. Large quantities of sarin of a higher concentration were thought to have been used in the Matsumoto attack, and intubation was difficult due to airway spasm and excessive airway secretion. Therefore, if the use of a nerve agent is suspected clinically, at a minimum, atropine sulfate should be administered as quickly as possible. It is therefore important to establish a system whereby antidotes can be administered early during pre-hospital care. 

Prior to plans for the destruction of the CW stockpiles of most countries, and preceding the sarin attacks in Matsumoto and Tokyo, the development and implementation of defensive measures against CW agents was primarily centered on the mihtary use... 

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