The Matsumoto Incident
Sarin Poisoning in a Japanese Residential Community
This document was prepared in the Fall of 1994, preceding the March 20, 1995 subway gas attack in Tokyo by several months.
INTRODUCTION
Late on the evening of June 27, 1994, authorities in Matsumoto, Japan began to receive calls from frightened citizens in Kaichi Heights, a neighborhood near the old heart of the city. Over the next several hours, emergency responders would transfer dozens of persons to area hospitals where they would be treated for acute exposure to toxic chemicals. Doctors were astonished to find dramatically reduced cholinesterase levels in virtually all the victims, and followed a course of treatment for organophosphoric poisoning.
Through the efforts of the medical teams, several very seriously afflicted persons were saved, while others with less severe symptoms received appropriate treatment and were made comfortable. Some cases, however, were beyond help. The toll would ultimately number seven dead and more than 200 injured, with a number of the injured requiring lengthy hospital stays. One survivor suffered permanent and massive brain damage.
Subsequent sampling and analysis identified the presence of the supertoxic nerve gas sarin -- a true chemical weapon -- at several sites in the affected area.
I had the opportunity to visit Matsumoto in December, 1994, for the purpose of collecting information on this case, which has been little reported outside of Japan. The following pages detail my findings, based on interviews with victims, medical personnel, and government officials in Matsumoto. In addition, it reflects information compiled and reported by Japanese sources.
JUNE 27, 1994
Matsumoto is located 100 miles west of Tokyo on the Japanese main island of Honshu. An industrial and tourist city of several hundred thousand people, it sits at the feet of the rugged Japanese Alps. The city is still dominated by the majestic moated castle constructed by a powerful daimyo nearly 400 years ago.
On June 27, between 8:00 PM and midnight, overwhelming evidence indicates sarin gas was released in the Kaichi Heights area. The gas was apparently generated or released from a vacant lot, near a small fishpond. Although no containers or related equipment were found, significant damage to plant life that occurred that evening -- apparently caused by another gas (HF?) released at the same time as the sarin -- radiated from that point. In addition, dead fish found in the pond, and the water and soil in the immediate area, showed traces of sarin.
While the trees around the fish pond and the darkness of night apparently prevented anyone from observing the exact source of the gas, there were several reports of odd, sharp smells. Two witnesses reported seeing a white, mist-like cloud emanate from the area.
CHRONOLOGY
The following is an edited chronology of the events on the night of June 27, 1994 and the following days:
11:00 PM: A man visiting a friend in the neighborhood suddenly complained of a headache, dizziness, and narrowing of vision.
11:09 PM: A call was received by Matsumoto emergency officials from a man saying that his wife was in pain and asking for an ambulance. The fire department medical team that arrived five minutes later was greeted by the husband, who was disoriented and ill himself. The couple and one of their daughters was transported to Kyoritsu Hospital, the wife receiving CPR from the emergency medical technicians.
11:30 PM: Police were notified by the fire department of the "accident". All officers were placed on alert. There were numerous emergency calls, and many victims were taken to hospitals by ambulance.
12:45 PM: Police used loudspeakers to warn persons of the toxic gases and to close their windows and doors.
1:00 AM: A police officer patrolling the area complained of stinging eyes.
1:20 AM: A shout from the Meiji Life Insurance Co. dormitory summoned help for a collapsed person on the 3rd floor, who ultimately died.
2:45 AM: Twelve out of eighteen persons brought in to Kyoritsu Hospital were hospitalized. Nurses handling the intake of victims, and in close physical proximity to them, subsequently reported having symptoms similar to those of the patients they assisted. Doctors observed physical symptoms of constricted pupils, nausea, and spasms, while blood test revealed severely depleted cholinesterase levels in the persons brought to the hospital. Assuming organophosphoric poisoning of some kind, physicians prescribed atropine injections. Subsequent interviews with doctors also indicated a pattern of excessive salivation (a secondary symptom linked to sarin) by many victims.
4:15 AM: Police announced that six persons had died. Another death was reported later that day.
5:00 AM: Five police officers investigating the scene were taken to Marinouchi Hospital complaining of nausea and stinging eyes.
5:35 AM: Rescuers wearing protective clothing and portable air supplies entered Kaichi Heights.
7:00 AM: Matsumoto police set up a special investigation headquarters to look into the "accident".
10:30 AM: The city established a command post to work out a solution to the poison gas.
11:00 AM: Investigators from the Matsumoto Health Center checked the air and water in Kaichi Heights. Chief Yoko Midorikawa announced that, based on the symptoms of the victims, it appeared the toxic chemical is an organophosphorus compound.
3:00 PM: The Department of Medicine at Shinshu University conducted autopsies on three of the seven dead.
July 3: Local police authorities announced that they had found residual traces of the nerve gas, "sarin", at six different sites in the Kaichi Heights. The identity of the nerve gas was determined through gas chromatography of samples taken in the afflicted neighborhood.
ANALYSIS
Although the events in Matsumoto prompted tremendous media speculation in Japan, the national authorities have publicly deemed the event to be a matter for the local police. There is, however, some reason to believe that considerable investigative activity is taking place within the Japanese intelligence and counter-terrorism establishments. Perhaps out of a desire to prevent panic, Japanese officials have played down the Matsumoto event and avoided speculation -- and even comment -- on the matter.
A better understanding of the threat posed by sarin may help explain why the authorities have apparently decided to downplay the Matsumoto incident.
Sarin is an organophosphorus compound first developed by German scientists during the late 1930's. Although derived from research related to the production of pesticides, it was specifically intended for military use as a chemical weapon. It is one of the most aggressively lethal substances known to chemical science, with an LD50 (lethal dose) of less than 0.1 milligram per kilogram. That is, for a typical person of 60 kilograms (132 pounds) weight, a drop containing less than 6 milligrams (approximately 0.0002 ounce) of sarin in contact with the skin will result in death in at least 50% of the cases.
Sarin was produced by combatants on both sides during World War II, but was never used. Although Germany shared the formula for sarin with its Axis partner, Japan, during that conflict, there is no clear evidence that Tokyo ever went ahead with production. Sarin is still present in the arsenals of the United States and Russian Federation, though both countries have pledged to destroy their inventories of all chemical arms by early in the next century.
There are several paths of manufacture for sarin, and these are widely known and documented in the open literature. The compound has no commercial applications, although it is produced from chemicals that are openly available to civilian buyers. Two of the precursor chemicals, hydrogen fluoride and isopropyl alcohol, are produced globally in extremely large volumes. While not exactly easy to make, the synthesis of sarin relies upon widely available technology dating back more than 50 years. The conclusion -- and fear -- of many experts is that nerve gases such as sarin are well within the technical capabilities of developing countries and terrorist groups.
The possibility that Matsumoto may have been the site of such a terrorist use is supported by several factors in the case.
First, sarin is the product of a specific and rather complex series of chemical processes. While well within the capabilities of a technically proficient chemist, the production of sarin is simply not something that can be done by accident. Some of the chemicals used in the manufacture of the gas are both toxic and difficult to obtain, and must be combined in a precise fashion, usually at high temperatures, to produce the nerve gas. The sarin at Matsumoto must have been deliberately formulated.
Second, weather conditions play a major role in the lethality of sarin. Rain both cleans the air of vapors, such as sarin, and neutralizes the nerve agent through hydrolysis; in addition, sarin, a volatile liquid, remains a vapor longer at warmer temperatures. June in Matsumoto is the rainy season, with steady showers and temperatures hovering around 20 C. On June 26, the weather changed abruptly. The skies cleared and the temperatures climbed to 30 C. Forecasters predicted the dry, warm conditions would last until June 28. The sarin poisonings took place on the evening of the second day, suggesting someone anticipated a break in the weather and took advantage of it.
Finally, the apparent absence of hard evidence such as the container used to transport or generate the nerve gas indicates a planned effort to conceal the identity of the person or persons responsible for the act. Initial theories of an experiment gone wrong, or some inadvertent mixing of toxic chemicals foundered as much on the "missing" equipment as on the scientific improbabilities. Possible explanations for the container's absence include that the container was composed of a material that decomposed or melted under the heat of the reaction, that the perpetrator or an accomplice removed the container during the confusion of the emergency response, and that the authorities actually recovered something and are keeping quiet about it.
Arguments against the terrorism theory center on the absence of both a clearly defined target in the Kaichi Heights area (indeed, in all of Matsumoto) and the apparent failure of any person or group to follow-up on the event with the usual trappings of such an action, i.e., messages to the media claiming credit, messages blaming authorities for forcing the attack, threats about another attack, etc. Several possible answers suggest themselves. One of the more compelling is that the Matsumoto attack was essentially an "experiment", designed by the sarin makers to test their technology, their ability to carry off such an assault successfully, and the deadly effectiveness of their weapon. The "experiment" theory may be further supported by reports that an investigation of complaints of headaches and nausea from the inhabitants of a village about an hours drive south of Matsumoto turned up chemicals in the environment authorities acknowledge were likely the degradation products of sarin.
It is not far-fetched to postulate a small group of persons (their motivations being beyond the scope of this paper) carefully testing and evaluating the effectiveness of a weapon based on a technology with which they are unfamiliar. Such testing would be prudent prior to planning a major strike using the new weapons, both to prevent accidents and to assure maximum effectiveness. It may also be that the unknown nature of the hand wielding the weapon plays as part of the group's strategy, or perhaps a desire for optimum surprise and shock. It any case, the person(s) responsible for Matsumoto certainly understand now that a significant quantity of nerve gas, delivered into a warm, crowded urban site (such as a Ginza department store, or major subway station) could have catastrophic consequences.
CONCLUSION
The Matsumoto incident has generally been referred to by authorities and the media in Japan as "the accident". There is compelling evidence that whatever the complete story of that deadly June night turns out to be, the events in that quiet city were anything but accidental. This case deserves further attention as the potential harbinger of the next phase of terrorist horror.