Comparative Sensitivity Thresholds

Figure 2 shows the comparative sensitivities of the chemical detection equipment used by the United States, France, and Czechoslovakia in the Gulf War. The sensitivity of a chemical agent detector is determined by how high the concentration of agent must be in the sample before the detector will indicate the presence of chemical agents. A detector that requires a lower concentration of agent to alarm is said to have a low threshold. The lower the threshold, the more sensitive the equipment.

Figure 2. Chemical Detector Sensitivity Thresholds to G-Series Nerve Agents (Air)

Since most US detectors are less sensitive[33] than the Czech and possibly less sensitive than French detectors discussed above, they might be unable, in certain cases, to detect or confirm the presence of low (below casualty thresholds) levels of chemical agents. Unlike the Czech detectors, US equipment was designed to detect concentrations of chemical agents that pose a direct and immediate threat to a soldier’s health.[34] It is important to note that the Czech CHP-71 and the US M256A1 Kit are equally as sensitive when testing for the presence of Mustard. The sensitivity threshold for both pieces of detection equipment for Mustard agent is approximately 1 mg/l3.

Czech and French Reported Chemical Agent Detections

On January 17, 1991, the Coalition forces began the Air Campaign with extensive attacks on targets in Iraq. Some of the facilities that were targeted during the early phases of the Air Campaign were suspected chemical and biological agent production plants and chemical weapon and biological weapon storage bunkers.[35]

Two days after the start of the Air Campaign, Czech and French units began reporting several possible detections of chemical agents. The chemical agents were detected in the vicinities of Hafar al Batin and King Khalid Military City (KKMC) from January 19 to January 24, 1991.

The following sections of this narrative describe the reported detections, and provide analyses of each reported incident. Table 1 contains a brief summary of both the Czech and the French reports of chemical detections. The descriptions of the chemical incidents are derived from the Ministry of Defense Report of the Czech Republic, CENTCOM NBC logs, unit logs and other available miscellaneous sources.

Table 1. Czech and French Reported Chemical Agent Detections

Date Reporting Country Type of Agent Detected Location
January 19, 1991 Czech Republic Sarin North and Northwest of Hafar Al Batin
January 19, 1991 Czech Republic Mustard KKMC
January 19 or 20, 1991 France Nerve and Blister Approximately 30 km from KKMC
January 20 or 21, 1991 Czech Republic and France Nerve Agent Unknown location
January 21, 1991 France Nerve and Blister KKMC Area
January 24, 1991 Czech Republic Blister North of KKMC
January 24 or 25, 1991 France Nerve and Mustard South of KKMC

The Ministry of Defense of the Czech Republic has acknowledged two detections; the January 19, 1991, detection of Sarin at Hafar al Batin and the detection of Mustard agent outside of KKMC on January 24, 1991.[36] Due to the processes used to detect the chemical agents, the United States DoD and the Intelligence community have labeled these two Czech detections as "valid" or "credible," however, other Coalition forces’ attempts to verify detections were not successful.[37] The government of France has not released any information regarding their reported detections; when this information becomes available it will be incorporated into an update of this case narrative.

Incident 1 - Czech Sarin Detection January 19, 1991

In the morning to early-afternoon on January 19, 1991, two Czech units, one unit supporting the 4th Saudi brigade and one supporting the 20th Saudi brigade, reported low level nerve agent detections. At the time of the detections, the Czech unit supporting the 4th brigade was on convoy and was divided into two detachments separated by approximately two kilometers. The two detachments reported almost simultaneous detections at their location about 37 kilometers northwest of Hafar Al Batin and 40 kilometers from the Iraqi border.[38] (Figure 3) According to the Czechs, about 30 minutes after the detections by the detachments supporting the 4th brigade, the unit supporting the 20th Saudi brigade reported a nerve agent detection approximately 45 kilometers northeast of Hafar Al Batin and 40 kilometers from the Kuwaiti border.[39] The Czech Republic considers all three of these detections to be "one event."[40]

Figure 3. Kuwaiti Theater of Operations with Incident 1, January 19, 1991

Using their automatic nerve agent detectors in the semi-continuous mode, both Czech units detected the initial presence of nerve agent. The concentration of Sarin in the air sample was determined to be between 0.05 and 0.005 milligrams per cubic meter (low levels of chemical agent). Subsequently, in all three incidents, the troops donned their protective gear and conducted follow up tests using their CHP-71. The follow up tests also indicated the presence of nerve agent.[41] Because both the automatic nerve agent detector and the CHP-71 are based on the same biochemical principles, the CHP-71 raised the confidence of the initial alert but did not confirm the results of the automatic nerve agent detector. At least one of the Czech units collected an air sample[42] on a dried silica gel substrate for further testing at their mobile chemical laboratory in KKMC. There, it was determined that the sample contained the nerve agent Sarin (GB).[43]

At the time of the detections, the Czechs observed no SCUD missile launches or impacts, artillery attacks, or other events that would suggest Iraq was firing chemical weapons. The Czechs also did not see any of the symptoms that are typically associated with chemical agent exposure, such as eye, nose or breathing problems. It is not surprising that Czech personnel did not exhibit symptoms of chemical exposure, because the detection levels reported by the Czechs were below the levels that would cause these symptoms to appear. Furthermore, no other units in the area reported chemical agent detections, however, again the levels reported by the Czechs were below the sensitivity thresholds of other Coalition detection equipment.[44] [45]

The Czechs reported these detections through the brigade headquarters to the joint command in KKMC. A situation report was filed for the detections and forwarded through the Saudi military to Riyadh.[46] When CENTCOM received this information, US chemical specialists were sent to the area to conduct additional chemical agent testing and analysis. It is estimated that four hours elapsed between the initial Czech detections and the arrival of the US specialists. The US chemical team was not able to confirm the Czech detections. Given the non-persistent nature of Sarin, the amount of time that had elapsed, the low levels detected, and the apparent localized nature of the chemicals, DIA determined that the results of the US chemical team were not surprising.[47] The CENTCOM NBC logs do not note the report of this chemical detection.

Analysis of Incident 1

Former Secretary of Defense Les Aspin characterized this incident as valid[48] and members of PGIIT and the Central Intelligence Agency (CIA) called it credible.[49] Their assessments were based on the known capabilities of the Czech chemical detection equipment, as well as the known processes used by the Czech personnel. The US has been unable to confirm these detections with US equipment and no air samples were saved for further testing. The Czech personnel used two different pieces of detection equipment (the CHP-71 and the mobile lab) that were based on different biochemical principles. The automatic nerve agent detector and the CHP-71 were used for the initial detection. In addition, the sample collected and taken to the mobile lab further corroborated the results of the initial field tests.

At the time that these detections were reported, it was thought that fallout from Coalition bombing of chemical weapons production and storage facilities in Iraq may have been the source of the chemical agent.[50] During the Gulf War, the Deputy Chemical Officer for Army Central Command (ARCENT) and the ARCENT Weather Officer looked into the fallout theory as a possible explanation for these detections. After plotting the winds for the days in question, both officers concluded that the fallout explanation "just didn’t add up."[51]

Although the idea of chemical fallout was dismissed as a possible source for these detections during the war, the idea was revisited after the war. As a result of in-depth modeling analysis, the Intelligence Community also concluded that fallout from bombed Iraqi facilities was not the cause of the Czech nerve vapor detections near Hafar al Batin. This assessment was based on the extensive dispersion that would have been expected between Iraqi chemical facilities and the locations of this detection and the modeling of weather conditions that included rain and southerly winds on January 17th and 18th. The weather modeling, combined with a lack of Iraqi casualties that would have been expected from a release large enough to cause the Czech detection formed the basis of the Intelligence Community’s assessment.[52] However, a former staff member of the Senate’s Committee on Banking, Housing, and Urban Affairs offered an alternative theory. In a report, the staff member postulated that the "winds aloft" rather than surface winds, trapped fallout from the bombing of Iraqi chemical sites and carried the chemicals to the locations of the detections. Although this claim cannot be fully accepted nor rejected, the staff member’s analysis is based on releases occurring during the early morning hours on the day of the detections.[53] However, this investigation has discovered no releases from chemical facilities on the dates of the Czech and French detections. This investigation’s analysis is explained in the following paragraphs and more information will be published in a separate information paper titled The Air Campaign.

After the war, Iraq claimed that only five percent of the approximately 700 metric tons of its declared chemical agent stockpile was actually destroyed by Coalition bombing. Coalition bombing did not cause more extensive damage to Iraq’s chemical stockpile because, in many cases, the Iraqis did not store chemical munitions in bunkers that they believed would be targeted by the Coalition. Instead, the chemical weapons were often stored in open areas in the desert that were not generally targeted by Coalition forces. According to a CIA study, by the start of the Air Campaign, the Iraqis had also shut down or dismantled the majority of their chemical weapon and precursor production lines.[54]

A total of four known Iraqi munitions facilities that were struck by Coalition bombs, considerably distant from Hafar Al Batin (Figure 4), have been identified as having contained filled chemical munitions. The facilities are An Nasiriyah, Muhammadiyat, Al Muthanna (also known as Samarra), and Ukhaydir. After reviewing raw intelligence and damage assessments from Coalition bombings in the seven years since the war, the CIA has concluded that Coalition bombing caused damage at Muhammadiyat, Al Muthanna, and Ukhaydir that could have released chemical agent.[55] [56]Chemical munitions were also identified as being stored at An Nasiriyah during the first Coalition bombing, but no munitions were damaged as a result.[57] More information about the bombings of these facilities and the resulting damage will be published in forthcoming case narratives.

Figure 4. Distances of Chemical Storage Sites from Hafar Al Batin


The earliest possible release date for Al Muthanna has been determined to be on the morning of February 8, 1991. Initial modeling, using the best data then available, showed that this release would not have caused the Czech and French detections. However, a combined DoD and CIA team, the same team that produced the model of the Khamisiyah plume, is again modeling the fallout that could have resulted from the bombing of Al Muthanna. Nevertheless, since the earliest release dates at Al Muthanna are after the date of the Czech and French detections, Al Muthanna can be ruled out as a source for the detections.[58]

The earliest possible date chemical agent could have been released by the bombing of Ukhaydir is January 20, 1991. This date is clearly after the Sarin detections on January 19th.[59]

Due to the complexity of the Muhammadiyat storage area, it is difficult to assess when or if Coalition bombing caused a release of agents. The earliest bombing date of the facility occurred January 19, 1991 and continued throughout the war. However, according to a CIA report, the worst case modeling of "all possible bombing dates to find the largest most southerly hazardous area," showed that "downwind dispersions in the general southerly direction for Sarin and Mustard fall below [the general population limit] at about 300 and 130 kilometers, respectively."[60] This is well short of the 620 kilometer distance between Muhammadiyat and the Czechs location at Hafar al Batin.

Although the An Nasiriyah facility, located 280 kilometers from the Czech location in Hafar al Batin, was bombed on January 17th, the bunker that contained chemical munitions was not damaged.[61] In May 1996, a United Nations Special Commission (UNSCOM) inspection team spoke with Iraqi representatives, and inspected the bunkers at An Nasiriyah. Iraqi representatives informed UNSCOM officials that approximately 6,000 Mustard-filled munitions were moved from Al Muthanna to An Nasiriyah by January 15, 1991, and stored in bunker number eight. On January 17, 1991, several of the structures at An Nasiriyah were destroyed by aerial bombing, but bunker eight was not hit.[62] At the end of their inspection of the An Nasiriyah facility, UNSCOM inspectors concluded that Coalition bombing did not cause any damage to bunker eight. UNSCOM also concluded that, by the time Coalition occupational forces destroyed bunker eight, the chemical munitions had been removed and only conventional munitions were left in the facility.[63] [64]

Another possible cause of the Czech detection was thought to be the presence of interferents, such as insecticides, petroleum products, chemical plant emissions, and pesticides used by the Coalition forces in the area of the Czech detections. However, after a thorough review of the geographic area surrounding the Czech detections, DIA found it unlikely that these interferents caused the Czech detection equipment to alarm. DIA assessed the area as a sparsely populated desert region with no agriculture, no industry, and no likely source of interferents. The only petrochemical facility in the vicinity was a fuel storage area that supplied oil to an adjacent power plant. Analysis of the Czech equipment and procedures used to detect chemical warfare agents supports the theory that petroleum products, exhaust gases from heavy equipment, etc., would not interfere with the Czech chemical detection equipment. Finally, DIA examined the possibility that pesticides used by Coalition forces caused the alarms, but this explanation was also found to be unlikely.[65]

Although several possible explanations for the Czech detections have been advanced, both during and subsequent to the Gulf War, the most frequently proposed source for the detections, chemical fallout from Coalition bombing and/or the possible presence for interferents, have been ruled out. Therefore, at this time, without additional information, investigators are unable to determine the source of the chemical agents detected in this incident.

Incident 2 - Czech Mustard Detection January 19, 1991

On January 19, 1991, the Czechs also reported a detection of Mustard agent in King Khalid Military City (KKMC). (Figure 5) This detection is identified in the Czech logs attached to their Ministry of Defense (MOD) report, and is also recorded in the CENTCOM NBC logs. A Czech Lieutenant Colonel also briefly mentioned this detection to Senator Shelby during his trip to Prague in January 1994. The Lieutenant Colonel told the Senator, "there had been another detection of Mustard in the air near the Engineer School in KKMC, 2-3 days prior to the detection on January 24."[66] Although he did not give a specific date, investigators believe that the Lieutenant Colonel was referring to the CENTCOM log entry of a Mustard detection on January 19th, also reported in the Czech Ministry of Defense report. The Czech Ministry of Defense report states that concentrations of the chemical agent Mustard were detected in the air. The report further states that the "concentrations (reported 0.002 g Yperite [Mustard]/m2 [sic]… without toxic agent specification) represent the limit of maximal admissible (threshold) concentration attacking the human body. Those were very isolated positive results of chemical reconnaissance which were confirmed by none of the other participating states."[67]

Figure 5. Kuwaiti Theater of Operations with Incident 2, January 19, 1991

The logs attached to the Czech MOD report contain an entry from January 19th, 12:10 PM Central European time. The entry states:

Two first line chemical battalions are concentrat[ed] in the rear part of the 20th brigade of the KSA’s [Kingdom of Saudi Arabia] armed forces.… In the area of our units detected 0.002g/m2 of Yperite. The unit is OK, ready to carry out its tasks.

Although reports of this detection appear in several places, the only detailed description of the events that surround this detection was found in an article, written by a Czech Major, that was published in a newsletter of a US NBC defense professional society. The Major’s account of events was written from notes he made in his personal notebook during the war.[68]

According to the Major, who was at KKMC when the event took place, the chemical alarm was announced at 10:45 AM. The commander of the squad at KKMC ordered his unit to don chemical protection gear and retreat to a shelter. The Major was assigned with a team to man a stationary chemical monitoring post outside the shelter’s entrance. The team used a CHP-71 to monitor for the presence of chemical agents.[69]

Before assuming monitoring duty, the Major’s squad received word that the Czech NBC reconnaissance squad had detected both Sarin and Mustard. The time difference between the report of the detection from the reconnaissance squad, located upwind from the shelter, and the shelter team’s first detection was approximately 30 minutes.[70] The NBC reconnaissance squad referenced in this incident probably is part of the same units described in Incident 1. However, (as previously described) that reconnaissance squad only reported low levels of Sarin.

Before taking over duty at the monitoring post, the Major took a new CHP-71 and checked its set of detection tubes. His intent was to eliminate "contamination of the inner surface of the entry pipe, [and] contamination of the entry filter in front of the detection tube by acid vapor, smoke and dirt," and because use of old detection tubes could possibly cause false positive readings.[71]

At noon, the Major assumed monitoring duty. At the time, he assessed the weather conditions as "a northwest wind at a speed of 3 meters per second (10.8 kilometers per hour) with an air temperature of 9� Celsius [sic] [48.2� Fahrenheit] with limited visibility." The Major’s personal account of the Mustard detection outside the shelter entrance is as follows:

My predecessor briefly informed me that Mustard (Yperite) was present in the air. In accordance with our protocols, I started to operate the CHP-71. In several minutes I saw a color change in the Mustard tube. The yellow color of the tube changed slightly to brown and a reddish brown ring appeared in the upper part of the charge .… [T]his was precisely as the provided standard showed for an Yperite concentration of 0.002 mg/L and higher. It was repeated three more times during one hour .… [I]n accordance with the detectors’ handling instructions, I also tested for the group of Sarin, Soman, and V-gases, Cyanogen chloride, hydrogen cyanide, phosgene, and disphosgene. All the results were all negative, except for the Mustard.[72]

At 1:15 PM the Major was relieved from duty, the observation post continued monitoring for the presence of chemical agents, but yielded negative results. Based on repeated negative results, the chemical alarm was called off at 2:30 PM.[73]

The results of the Major’s measurements were reported to the commander of the Czech unit. The article also states that the team collected air samples at the shelter entrance, but tests of the samples performed at the Czech mobile laboratory did not confirm the presence of Mustard agent. The Major postulated why a confirmation from the laboratory was not possible. In his opinion he doubted that the sample of contaminated air contained sufficient amounts of Mustard to produce the chemical reactions needed for the laboratory’s equipment. The article also discussed possible sources of the chemical agents detected. According to the Major, one conclusion was that the wind could have possibly picked up the secondary or tertiary aerosol clouds resulting from Coalition bombing of chemical facilities and stockpiles in Iraq.[74]

A team of US ARCENT personnel, stationed forward at KKMC, was involved in follow-up testing after the Czech detections. A Saudi Army officer brought this team to the location of the Czech detection. The team was told that some blister or nerve agent was present around KKMC. Before their arrival at the site, the ARCENT personnel put on their chemical protection gear, but the Saudi Officer did not use any protective measures. The team then broke into two smaller components and conducted several tests in the area of the original Czech detection. Using the M256A1 test kit, they tested for both Mustard and nerve agent. The tests yielded negative results and the unprotected Saudi officer did not show any symptoms of chemical agent poisoning. [75] The negative results of the ARCENT team’s tests are inconsistent with the presence of Mustard agent in the area. (Liquid Mustard agent is persistent and would most likely have remained in the area of the Czech detection for several days to weeks.[76]) About an hour after the conclusion of these tests, the US officer who led the team contacted the Czechs to discuss their detection. The only response he received was that the Czechs detected some sort of a blister agent.[77]

The CENTCOM NBC logs contain an entry reporting the Czechs detecting Mustard at KKMC. The entry of Jan 192246 (January 19 at 10:46 PM) reads, "Czech unit reported 2% HD in the air at KKMC at 1100hrs [11:00 AM], rising to 3% HD [Mustard] at 1300."[78] [79]

The CENTCOM NBC watch officers were functional and area experts. Their job was to monitor NBC events within theater so they could attempt to collect reports of the incidents. The watch officers collected as much information as possible about such events and provided it to the Operations Deputy and the J3, the General in charge of the Operations section of CENTCOM.[80]

There is no record of what CENTCOM did after receiving the Czech report. However, during post-war interviews, both watch officers on duty when the entry was made expressed their skepticism as to the validity of the Czech detections, based on their understanding of the sensitivity of the Czech equipment.

[A]t that time, [we were] not sure of the reliability of the Czech equipment. We were not especially familiar with the technical capabilities of the Czech chemical detection equipment. There was some speculation that it may have been more sensitive than the state of the art US systems at the time, but we did not have any … specific technical data to do a side by side comparison.[81]

Based on the information provided by the ARCENT team at KKMC and their understanding of the Czech’s detection capabilities, at the time of the detections the CENTCOM NBC watch officers determined that the Czech detections were not accurate. This assessment was based on a number of factors: 1. the absence of reports by other units that could have corroborated the presence of any sort of chemical agent within the atmosphere; 2. the distances between the known sites in Iraq that were bombed by Coalition forces and the area of the detection; and, 3. their assessment was based on their attempt to determine why the Czechs would provide reports that were a percentage of something in the air when detectors do not usually have the ability to give percentages.[82] This incident did not receive more attention from the watch officers because they felt there was no cause for concern. The Czechs underscored and highlighted the fact that the detection was below a safety threshold level.[83]

Analysis of Incident 2

The Czech team at the monitoring post used the CHP-71 for their initial detection, as well as for the confirmation tests. The sample of air the squad took for further testing at their mobile laboratory did not confirm the presence of Mustard agent when tested in the Czech mobile laboratory. Furthermore, other units in the vicinity of KKMC did not report similar chemical alarms. Subsequent tests by US ARCENT personnel also failed to confirm the presence of Mustard. Therefore, there was no confirmation of the detection using a different biochemical technique.

Although a Czech Lieutenant Colonel commented to Senator Shelby about hearing of another detection at about the same time, no further comments or details were provided to the Senator or other DoD representatives who have visited Prague inquiring about detections during the Gulf War. Furthermore, as with the January 19th Sarin detection (Incident 1), fallout from the bombing of the Iraqi chemical sites (Al Muthanna, Muhammadiyat and Ukhaydir) occurred after January 19th and, therefore, could not be a possible source of the Mustard agent for this detection. As noted above, it has also been determined that damage incurred at An Nasiriyah on January 17th, did not affect any bunkers containing chemical munitions. Thus, it is unlikely that a chemical release did not occur. Thus, it is unlikely that a chemical release did occur. corrected August 7, 1998, to reflect original hard copy distributed on August 4, 1998.

| First Page | Prev Page | Next Page |