Combined Chlorine/IED Incidents

Recent attacks in Iraq combining the use of explosives and chlorine have highlighted the fact that terrorists are constantly seeking more effective methods of attack. In the interest of public safety and current international trends, it is prudent for emergency responders to study these incidents and develop effective public safety guidelines. Globally, terrorists are learning to adapt their tactics and techniques and there is a good chance that these tactics will be seen in other locales.

This article will address the use of a "combined device" specifically consisting of chlorine and improvised explosive device (IED). Combined devices have also been referred to as "chemical bombs" or "dirty bombs." Also, these devices could be assembled using a wide variety of hazardous materials. The IED component of a combined device can be anything from homemade pipe bombs to sophisticated military ordnance, but nonmilitary first responders are more likely to encounter IEDs than military weapons in their day-to-day response activities.

It is important to study the sometimes-fatal lessons learned from these events and apply them to our preparing the "homeland" for any future incidents. In Iraq, from January to April 2007, there were at least nine chlorine attacks leading to over 50 fatalities and more than 500 injuries, including those to U.S service members. The attacks took place primarily in the areas of Baghdad, Fallujah and Ramadi. Most of them utilized a suicide bomber to move the combined device to the point of detonation. The chlorine containers varied from large tankers to small containers that could be carried in the back of a pickup. It has been discussed that chlorine may have been used because it is present in large quantities in Iraq to deal with the country's poor water sanitation.

This method of attack has so far been an extremely crude means of delivery. It appears in the attacks a large proportion of the chemicals are consumed in the explosions itself. It is not an efficient means of dispersal, but the insurgents continue to experiment and improve their methods of attack and dispersal using the combined devices. The Iraqi government can try to limit access to chlorine, but a strong black market exists. The primary impact so far has been to cause widespread panic, with large numbers of civilians suffering non life-threatening, but very traumatic injuries. This combined-device attack also targets responders, making it difficult for them to respond to the scene. Numerous U.S. soldiers have reported the difficulty of trying to respond to and manage the incidents due to the chlorine.

Combined Devices
A possible combined device can be found during the response to an explosives response, answering a suspicious package/container call, or when conducting routine activities such as investigations and inspections. IEDs can be designed to be concealed or look like ordinary items. The exterior inspection of a suspected device does not ensure its safety:

  • Responders should always be very cautious of any item that arouses your curiosity.
  • Large or small containers with unknown liquids or materials.
  • Unusual devices or containers with electronic components such as wires, circuit boards, cellular phones, antennas and other items attached or exposed.
  • Devices containing quantities of fuses, fireworks, match heads, black powder, smokeless powder, incendiary materials or other unusual materials.
  • Materials attached to or surrounding an item such as nails, bolts, drill bits or marbles that could be used for shrapnel.
  • Ordnance such as blasting caps, military explosives, commercial explosives and grenades.
  • Any combination of the above items.

Chlorine is a greenish-yellow diatomic gas. It is normally shipped as a liquefied, compressed gas in 100- to 150-pound cylinders, ton cylinders and railroad cars. The vapor density of chlorine is 2.5, which means that it is considerably heavier than air and will travel along the ground and sink into low-lying areas. The expansion ratio for liquefied chlorine (liquid to vapor) is 450-500 to 1. This means that a small amount of liquefied chlorine, when released from its container, will produce a significant vapor cloud.

Although chlorine is not flammable, it is a strong oxidizer and will support combustion. When a combined device is detonated, some of the chlorine will be consumed in the explosion. Emergency responders should, however, plan for the potential of a significant and immediate release of chlorine gas along with debris from the compressed gas container. Chlorine is highly toxic by all routes of entry - inhalation, absorption, ingestion and injection - and is corrosive to the skin and mucus membranes like eyes and lungs. Chlorine gas will mix with body moisture to form hydrochloric acid, causing immediate and dangerous chemical burns.

The initial exposure concern with chlorine is the inhalation hazard. Emergency responders with immediate access to self-contained breathing apparatus (SCBA) have a means for self-protection. Many EMS and law enforcement personnel, however, do not have the availability of SCBA in their vehicles, and therefore are at great risk for respiratory exposure immediately following a chlorine release. And while chlorine's warning properties (odor and irritation) generally provide adequate notice of a hazardous environment, immediate egress must be available and utilized.

Although large-scale releases of chlorine through the use of a combined device will normally occur in or near outdoor venues, personnel should always be prepared to encounter hazardous atmospheres inside enclosed structures as well. Appropriate use of personal protective equipment (PPE) to include SCBA will be essential for the health and safety of the emergency responder. Chlorine is a skin irritant in addition to being a respiratory hazard. Standard turnout gear and duty uniforms do not provide sufficient protection from chlorine for anything more than rapid rescue and egress operations.

Properly trained and equipped hazmat technicians should be employed for monitoring, containment and remediation operations. Understandably, many jurisdictions may not have immediate access to a hazmat team and may feel compelled to provide some initial action. Rescue activities may be within the purview of local emergency response agencies, but should be documented in standard operating guidelines (SOGs) and protocols. The decision to deploy responders with limited chemical protection and training is a difficult one and will vary by jurisdiction.

Certain precautions can be taken to limit exposure to chlorine by first responders engaged in the initial rescue operations. Approach the scene from an upwind and uphill posture and be mindful of the likelihood of secondary devices targeted at emergency personnel. Ensure that responders don SCBA and all available PPE. The key is to minimize exposure to the chemical as well as the time exposed. Entry into a contaminated structure by the initial emergency responders for anything other than immediate rescue and egress should be discouraged.

Responders should be prepared for a significant number of civilian casualties resulting from exposure to both chlorine and debris/shrapnel from the explosion. All victims should be relocated to a fresh-air environment and triaged. In many cases, just moving patients out of the chlorine vapors will provide immediate relief. More severely exposed patients, however, will require rapid decontamination.

The decontamination process should not be delayed until the arrival of a hazmat team, but rather initiated by first responders. A hoseline and some common sense is all that is required for the initial phase of decon. Victims should be thoroughly flushed with water and then any contaminated clothing should be removed carefully. Responders should be dressed in full PPE with SCBA and consult with hazmat and EMS personnel for further guidance and local protocols.

While most hazmat technicians are well versed in the properties of chlorine, the first responder community at large may not have as thorough an understanding. Company-level training should include review of local policies on IED/combined device response, including a basic overview of chemical hazards. Several free resources are available to emergency responders, including the North American Emergency Response Guidebook (ERG) and computer software like CAMEO and WISER. Training evolutions should be conducted on a regular basis.

The last significant release or chlorine in the United States, although not a terrorist attack, certainly demonstrated the inherent dangers of this highly toxic gas. On Jan. 6, 2005 in Graniteville, SC, two trains collided, causing the release of 90 tons of chlorine from a rail car. Nine fatalities were reported with over 250 people injured and 5,400 residents evacuated. Long-term effects of the chlorine exposure are still being reviewed.

The use of chlorine in a combined device may not create a multi-fatal event, but it will certainly evoke panic and fear that will hamper the efforts of emergency responders. It is important that all emergency personnel understand the hazards of chlorine as a component of an IED and are prepared to respond accordingly. Appropriate training and PPE will be critical for a safe response.


The information presented here is intended to help agencies with their planning and training efforts. The more our public safety agencies prepare, the better they are prepared to respond to effectively and safely manage any type of situation that might arise. The community has entrusted us with their safety, so let's prepare now!

AUGUST VERNON is an assistant coordinator for Forsyth County Emergency Management in Winston-Salem, NC. He returned in 2005 to his position at Emergency Management after a year in Iraq as a security contractor conducting long-range heavy convoy security operations involved in several IED and combative engagements. Vernon has been a member of emergency management since 2000, a member of the fire service since 1990 and a fire service instructor. He also served in the U.S. Army as an NBC (nuclear, biological and chemical) Operations Specialist. Vernon teaches courses in incident management, OPSEC for Public Safety, hazmat operations and terrorism/WMD response. Vernon may be reached at STEVE MARKS, an assistant coordinator for Guilford County Emergency Management in Greensboro, NC, has been involved in emergency services since 1982 with experience in fire, EMS and hazmat operations. He presently specializes in emergency preparedness and disaster response. Marks have been instructing since 1988 and is an adjunct faculty member at the Emergency Management Institute in Emmitsburg, MD, and the University of North Carolina in Charlotte. He is completing a master of science degree in emergency management at Jacksonville State University in Alabama. Marks may be reached at