Chlorine Gas: Munition or Commodity?

More years ago than I like to admit to (I think close to 30), I wrote an article for IFW on chlorine. In this article, I treated chlorine as a chemical commodity with many uses beneficial to people the world over, which it certainly is.

During the ensuing decades, however, “times have changed” and the horrific reports coming out of the Middle East, recently, have made it appropriate to revisit this topic with focus not upon the positive aspects of chlorine in the areas of Public Health, pharmaceutical formulation and product formulation but upon the negative attributes that made chlorine so successful as the first “war gas.”

It is indeed unfortunate that this state of affairs has come to pass but “it is what is,” and I have revisited chlorine in the hope that my small contribution may engender a heightened sense of urgency and increased awareness of the risks of allowing this material to get into the hands of those who would do us harm. 

On Wednesday, April 4, 2018, the small Syrian town of Khan Sheikhoun was subjected to an aerial attack by the forces of the Syrian government under Bashar Assad. The air-strike wounded hundreds and killed more than 80 people, including at least 20 women and 30 children.

Shortly after the attack, photos, videos, and written reports of the carnage began pouring in and it quickly became clear to experts that something other than conventional weaponry had been used in the attack. Victims described running from toxic gases, with those who could not escape allegedly choking and foaming at the mouth. Footage taken after the attack showed infants shaking uncontrollably.

These and other pieces of evidence pointed to the possible use of chemical weapons, and on Thursday, anonymous US officials told the associated press that “early assessments” showed the use of chlorine gas and traces of the nerve agent sarin in the attack.”

In view of these horrific revelations about Syria and its use of chemical weapons against its own people one cannot help but wonder can the same happen here? Unfortunately, there is a good chance that the answer is likely to be “yes.”

This possibility is not a reflection on the government, the military or the citizenry but stems from the nature of the agents used in the attack. Sarin, or NATO designation GB (G-series, “B”), is a highly toxic synthetic organophosphorus compound. A colorless, odorless liquid, it is used as a chemical weapon due to its extreme potency as a nerve agent.  As of this writing, this compound has little or no use other than as a weapon and therefore strict control of its location and ownership is a practical possibility.

Chlorine, on the other hand, is not only a war gas but it is an essential chemical raw material and intermediary. It was this very property that led to the weaponization of this element and the introduction of “gas warfare” into the lexicon of military weaponry.

Chlorine was first prepared as a pure substance by Carl Wilhelm Scheele. In 1774 Scheele wrote a description of the gas supposing it to be an oxide of a new element. In 1809, chemists suggested that the gas itself might be a pure element, and this was confirmed by Sir Humphrey Davy in 1810, who named it from ancient Greek χλωρός, translit. khlôros, lit. ‹pale green› based on its color.

Chlorine (atomic number 17, atomic weight 35.45) is the second most common element in the earth’s crust occurring mainly as Sodium Chloride (NaCl). It is highly reactive and therefore is never found free in nature.  

Elemental Chlorine occurs as a pale green gas with a distinctive acrid odor. The gas has the formula Cl2. Chlorine has an outer ring configuration of 7 electrons and therefore forms diatomic molecules (Cl2) when in the elemental state.

Chlorine is not only cheap, it is easy to prepare; the process requiring only a brine (salt water) and a source of electricity (Direct current, a DC welding machine will do). When the electrolytic cell is operating, chlorine (Cl2) is liberated at the anode and lye (Sodium hydroxide. NaOH) is released at the Cathode.

In the Downs process the reactions are the same but instead of brine the electric current is applied to molten (“fused”) sodium chloride (NaCl) or rock salt. The annodic product is Cl2, as before, and the cathodic product is sodium metal (Na). If potassium chloride (KCl) is substituted for the NaCl the cathodic product is potassium metal (K) and this is the process utilized for the production of these metals.

The bottom line is simple. Chlorine is cheap and easy to procure either by purchase or by preparation. It is also very useful, even essential, to modern life in the 21st century,

While the uses of chlorine are myriad, the most widely visible use is for the purification of drinking water and disinfection of waste water. Trucks carrying “one ton ” cylinders and tank cars containing chlorine are a common sight along the nation’s highways and railroads. This widespread utilization of chlorine has, of course, helped to make our modern urban society possible.

Take the case of water purification alone: Before the routine use of chlorine in U.S. water supplies, typhoid fever claimed 25,000 fatalities each year. Today 98 percent of public water supplies are treated with chlorine or a chlorine compound. Typhoid fever now claims about one victim a year, on average.

Unfortunately the same element that has made safe water almost axiomatic in the U.S. has also been weaponized and has the dubious distinction of being the first “war gas.” Chlorine, also known as Bertholite, was first used as a weapon in World War I by Germany on April 22, 1915 at the Second Battle of Ypres. As described by the soldiers, it had the distinctive smell of a mixture of pepper and pineapple. It also tasted metallic and stung the back of the throat and chest.

Chlorine reacts with water in the mucosa of the lungs to form hydrochloric acid (HCl), destructive to living tissue and potentially lethal; facts that are consistent with symptoms exhibited by the victims of the attacks in Syria. Chlorine (or Bertholite) is just as effective as a weapon today as it was in 1915.

The physical properties of Chlorine make it very easy to utilize as a “weapon of mass destruction”. In the first place, chlorine is a gas under room conditions and is stored in cylinders as a liquid under moderate pressure. All that is required for effective deployment is to obtain a cylinder of chlorine, point it in the general direction of the target, knock off the valve (to prevent its being closed) and run.

There is no need for advance mixing or reagents or complicated dispersal mechanisms; just open the valve and get out of the way.

Given the widespread presence of Chlorine in our environment just how could this element be utilized as a Weapon of Mass Destruction (WMD) and what would the effects be? To answer these very pertinent questions, a few years ago I developed a “desk top” exercise to assess the effects of a large scale chlorine release and the community’s ability to respond to it. The results were astounding, to say the least.

To begin with I recruited a fellow who was a bit of a “maverick” and routinely “thought outside the box.” He was familiar with the community and the response capabilities therein.

This gentleman was assigned to be the “perpetrator” of the incident. He could be a suicide bomber, a careless truck driver, or an inept swimming pool operator, whatever he chose as his role. This “perpetrator” designed the incident as if he were actually going to carry it out. 

The rules governing this simulation are fairly simple and straightforward:

Everything is “real world” and “real time”. If the jurisdiction doesn’t have a 100’ ladder truck you can’t assign one. If, on the day selected for the exercise, Engine 12 is “out of service” to accomplish needed repairs, it is unavailable and cannot be utilized in the response.

The incident had to be plausible and conform to the community. If there is no rail service then don’t try to simulate a train wreck. The commodity involved in the simulated incident may be left up to the imagination of the perpetrator or it may be assigned (as this one was).

It is to be remembered that an incident on the highway could involve a hazmat that was “in transit” and would not normally be found in the local community.

The time and date of the simulated incident was kept secret and known only to that person responsible for the exercise. Once it had been set it was “poured in concrete.” If it fell on top of the Founders Day celebration so be it, this is reality.

The exercise was started by a telephone report just as would most likely happen in the real world. When the call came those involved responded just as they would in the event of an actual incident except for the fact that there was be no actual mobilization; no engines left the station.

Those running the exercise were fed information to those responding via telephone. This information could be adjusted as necessary to reflect the actions of the responders.

When the exercise was terminated there was, of course, a “lessons learned” session. If the exercise is properly planned this usually becomes an eye opening experience. It may also result in some changes in the jurisdictional response plan.

The scenario for the simulation that we mounted went as follows: Our city relies on ground water for our domestic supply. This water is obtained by means of a large number of wells situated in and around the city. Each of these wells is equipped with a chlorine injector at the well head which is supplied by a one ton cylinder located within a chain-link fence enclosure. Other cylinders, full and empty, are stored within the enclosure until connected to the system or, if empty, picked up by the supplier’s truck.

The simulated incident occurred on a night when there was a major athletic event at the local University’s event center, which would be expected to be filled to capacity or at least close to it. The “perpetrators” of this “incident” drove to one of the more remote municipal wells with a truck which was labeled as being the property of a well-known chlorine supplier who routinely did business with the city.

Entry into the enclosure was affected by simply cutting the chain securing the gate of the enclosure. The truck was loaded with a full one ton cylinder of Chlorine and driven away. Upon exiting the well site, the perpetrators wired up the chain so that it looked like it was intact and only a close inspection would have revealed the intrusion.

The truck was then driven to the Event Center at the university and parked beside the louvers over the intake for the air conditioning system, located in a poorly lighted alley. A small explosive charge, detonated by a timing device was set to destroy the valve and release the chlorine after a suitable time delay which allowed the perpetrators to make good their escape. A pipe slipped over the cylinder valve directed the chlorine into the air intake.

The exercise ran as advertised and a post event evaluation team composed of engineering and chemistry professors determined that had it been a “real world” event it would have succeeded beyond expectations. The number of deaths and injuries would have been horrendous to be sure, especially if the “perpetrators” had carried out their initial plan to block all the exits, but this is not the only consequence that would accrue to those who would instigate such an occurrence.

The biggest dividend, from the perpetrator’s point of view, is the fear that it strikes in the bystanders, both innocent and involved.

Webster defines terror as “violent or destructive acts (as bombing) committed by groups in order to intimidate a population or government into granting their demands”.

What would have happened in the event that our simulated incident had been “real” would certainly fit this definition.

The main objective of a terrorist attack is often not the killing of innocent people but the injuring of as many as possible. Once a victim has become deceased he no longer draws upon resources of his fellow responders. He can simply lie where he has fallen until the body is removed for burial.

A wounded person, on the other hand, continues to draw upon medical aid personnel, medical supplies, transportation and treatment facilities with the attendant personnel. These may, depending on the venue, require additional manpower for protection. Consequently a wounded victim creates more of a liability for his compatriots than does a dead one. Terror can also mean fear and the panic that in the case of an incident such as the one proposed in our exercise would engender can hardly be imagined.

Now, I am well aware that this column is supposed to deal with hazardous materials (hazmats) per se, but I am also aware that those of us who are engaged in the manufacture, transportation and/or consumption of these materials represent most of the available capability to deal with them in the event of an untoward incident and  that we have, at least, a  moral obligation to promote the safety and well-being of our fellow citizens in the event of an incident involving these commodities.

Accidents involving hazmats will happen in the course of normal commerce, and industry is, by and large, prepared to deal with them and, so far as is possible, mitigate the consequences though there is always room for improvement. Research by industry has produced numerous improvements in transportation and handling, such as the shelf coupler for tank cars, which have reduced the number of hazmat accidents substantially.

Unfortunately, as the number (and to some extent the severity) of hazmat incidents of industrial or transportation origin has declined there has been a concomitant increase in the number of  “terroristic” incidents deliberately designed for no other purpose than to kill, maim and otherwise instill terror in the innocent civilian population.  

There are numerous industrial materials that can be weaponized but none that can be so utilized to the extent or scale possible with chlorine. This is due largely to the tremendous amount (11.6 million short tons in 2010) of the element produced for legitimate purposes   (water purification and industrial formulation) as well as the low cost and ease of acquisition.

The need for chlorine in contemporary society is a given and cannot be reduced without invoking very serious consequences. The low cost of chlorine is not a significant factor for those who would try to use it in anti-social activities. These people are usually well financed or else they obtain their materials through pilferage. This leaves “ease of acquisition” as the one of the afore mentioned factors that would contribute to the choice of chlorine as a weapon of mass destruction.

Given the well-known hazards inherent in the utilization of chlorine, the ease with which this commodity can be obtained is surprising to say the least.

A few years ago a group of investigators in one of our major cities set out to see just how hard it would be to obtain a one ton cylinder of chlorine. They rented a building in the industrial neighborhood and then, having a legitimate address, simply called up a local chlorine supplier and ordered a one ton cylinder which, in due time was actually delivered; no questions asked.

Chlorine is not, by any means, the only hazmat that can be diverted for nefarious purposes but it is probably the most efficient. It exists as a liquid when confined at high pressure (around 50 lbs/in). It becomes a gas at room temperature (one volume of liquid chlorine expands to 450-500 volumes of chlorine gas). Chlorine does not have to be present in extremely high concentrations to be toxic; concentrations of about 400 ppm and beyond are generally fatal over 30 min. and at 1,000 ppm and above, fatality ensues within only a few minutes.

Consequently only a small amount of chlorine can contaminate a fairly large area. Chlorine is a relatively dense gas and tends to lie close to the ground thus, the possibility of inadvertent exposure of response personnel to toxic levels of the gas is maximized.  

“Familiarity breeds contempt” and in view of these aforementioned attributes of chlorine,  the  cavalier manner with which this commodity is sometimes handled in ordinary commerce gives rise to some valid and justifiable concerns. To date, there has been no report of any deliberate release of chlorine for nefarious purposes in the U.S. but, sooner or later, there will be and when this happens we will need to be prepared.

In the meantime there are a number of low cost measures that can be taken by the those engaged in the handling of chlorine, as well as other hazmats to help reduce the chance of inappropriate utilization of this element. These are not expensive, labor intensive, “high tech” measures but, rather, common sense applications of the oft repeated admonition “if you see something, say something.”

One could even go a step further, become a bit proactive, and look to see if there is any “something” that warrants further investigation. This “something” doesn’t necessarily have to be nefarious in nature; it could simply be the result of carelessness or an overlooked design error. I once encountered a one-ton chlorine cylinder sitting in the middle of a lawn surrounding an indoor swimming pool. This cylinder rested in a cradle made from a couple of four by fours without any protective enclosure whatever.

A ⅜-inch copper tube leading to the chlorine feed mechanism that supplied the pool emerged from the grass and was connected to the liquid valve of the cylinder. I couldn’t avoid wondering just how long it would be before some overzealous lawnmower jockey hit that tube and released a cloud of chlorine vapor.

A new order from a previously unknown customer can easily be “vetted” by a simple telephone call to check out the validity of the given address, the type of commercial activity being carried out and an approximation of the amount of chlorine needed.

The delivering driver should also be observant; is he being asked to unload the cylinder in or near an active commercial operation or to an empty warehouse? Do the receiving personnel have , and know how to utilize, the equipment required to handle chlorine containers? Was the order delivered to a facility that had, at least, the appearance of security? Were there security cameras in evidence?  Was the chlorine area enclosed by an adequate fence?

Lines of communication within companies need to be established and kept open at all times. Any delivery driver should feel free to walk into his boss’s office and say “I made a delivery to the “So and So company today and I didn’t see any sign of a security camera. The fellows who took the cylinder didn’t seem to know much about it and I didn’t see anything going on that would justify a one-ton cylinder of chlorine.” In an extreme case drivers should be authorized to simply refuse to deliver the order and return it to the plant.

Accounting can also contribute to the emerging picture of a new customer without raising any adverse feelings that might have an adverse effect on an otherwise amicable commercial relationship.

How will payment for the shipment be made? Will it be made on receipt of invoice to an established account via some conventional medium such as a credit card, conventional bank account, letter of credit or other traceable documentation or will it be made at the time of delivery in cash which is, of course, non-traceable? Were payment arrangements agreed on in advance i.e. when the order was placed and are they normal for this customer?

All of these questions and their answers have the potential to arouse suspicions resulting in “false alarms” but it only takes one successful intervention to prevent a major incident.

Once a “red flag” has been noted the ball is in the court of law enforcement and emergency response organizations. These agencies need to consider and answer the usual questions pertaining to a chlorine incident such as: Where is/are the nearest chlorine kits (A, B, C) and are personnel available to deploy them? What areas will be impacted and will they need to be evacuated? If yes, how will this be accomplished?

While these questions are, at the moment, focused on chlorine it should be noted that they will apply to a great extent to any and all hazardous materials. This is especially true in the case of potential incidents involving commodities which are not normally found in the community but pass through unnoticed en-route to their final destination.

In reality this means that virtually anything can be found anywhere. A suburban community that gets its water from a nearby city and therefore does not have a water treatment plant cannot relax, secure in the knowledge that there is no chlorine within their jurisdiction; not with an Interstate highway going around town or a mainline railroad  running along the edge of a residential district. In short we reiterate the previous statement: we can have anything anywhere and as a result we need to take a page from the Boy Scouts’ play-book “be prepared” “an ounce of prevention is always worth a pound of cure.”