Tuesday, October 26, 2010

Security Issues – Chemical Reactions

An article from last week on KSL.com describes a chemical incident that is classic violation of industrial chemical safety 101; don’t mix incompatible chemicals. A closer reading of the article shows that the lesson should also apply to chemical security 101.

The Incident

A chemical delivery was taking place at an industrial facility. The driver was given the job of offloading the chemical into a vessel (the article calls it a vat, I’m not sure what that is) that was thought to be empty. It apparently was mainly empty, but it contained chemical residues. The chemical being off-loaded was sodium hypochlorite solution. The residues were hydrochloric acid (almost certainly a solution). Second year chemistry students should be able to explain what happened next; a chemical reaction producing chlorine gas.

The article quotes a facility spokesperson as saying: “There were fumes that overcame two of our employees. They started coughing and having burning sensations in their chests.” The small amounts of the chemicals involved probably saved the lives of the two people standing nearby. They were both taken to nearby hospitals and released later the same day.

Chemical Safety

Unintentional mixing of chemicals is something that should be avoided as a matter of policy. Most industrial chemicals are not going to react in a hazardous manner when being mixed with residues like this. Even so, quality issues and other consequences of contamination are more than reason enough to avoid such mixing.

There are some chemicals, however, which are very reactive and can cause all sorts of nasty consequences when mixed with other chemicals that could endanger employees, the facility, and neighbors. A key component of a chemical safety program is to identify those chemicals used on site that could react dangerously with other chemicals. Then the chemicals that they violently react with must be identified. Finally, the facility must establish procedures and protocols that keep the reactive chemicals physically separated.

There are some chemicals, like sodium hypochlorite, that react violently with such a wide variety of chemicals that it is almost easier to list the chemicals with which it doesn’t dangerously react. If chemicals like these are going to be off-loaded from a bulk truck or container into vessels or containers on-site, those containers should probably be dedicated to that service and not used for any other chemical.

I am not a big fan of allowing off-site personnel to unload bulk deliveries of chemicals, hazardous or otherwise. Such personnel are unlikely to be aware of the tell tale signs at a facility that they are attempting to unload something in the wrong place. Additionally, they are generally unaware of the other chemicals on-site that might present a specific hazard to the unloading operations.

The only exception to this is when a supplier driver is unloading into a tank on site that the supplier owns and only their drivers have the keys to open the unloading lines. Even then a prudent facility will have some way of verifying that the load is the correct chemical to be unloaded into that tank.

Chemical Security

The article notes that the “spill temporarily forced an evacuation at” the facility. From a chemical safety perspective this is a very reasonable precaution. Chlorine gas has a very small short term exposure limit and is very unpleasant to inhale at concentrations well below the lethal threshold.

Security personnel will readily recognize the security issue presented with that statement. An emergency evacuation is going to cause some level of confusion at even the best trained facility. This confusion could be a potential tool used to facilitate a successful penetration of the facility.

Security forces should not have secondary emergency response responsibilities. They should be trained to go to a heightened state of alert during other emergencies at the facility. Personnel monitoring security cameras and other security sensors should be physically isolated from chemical storage and process areas of the facility. This will make it easier for them to maintain surveillance during chemical emergencies.

Safety and Security

Once again we can see that there are both safety and security components of many actions in high-risk operations. A compromise of either compromises both. High-risk facilities need to get in the practice of examining both the security and safety consequences of anything that they do at the facility.

No comments:

/* Use this with templates/template-twocol.html */