Occupational Health & Safety

Combating the Unseen

First response teams should always check vendor references. Real-world use is the true acid test for gas detection instruments.

• By Alan Matta
• Mar 01, 2003

FIRST responders have the perilous task of stepping straight into hell--whether it's a burning building, toxic chemical spill, radiological disaster, or other hazardous materials situation. In these environments, first responders can take steps to protect themselves against known compounds, but the most dangerous threat is always the unknown.

Reactive gases often fall into the category of "unknown." Either they are colorless, odorless, or both, or they could be masked by more noticeable agents. A seemingly straightforward industrial accident could easily disguise the presence of a gas placed deliberately, such as sarin or mustard. This is the danger first responders face daily.

For these reasons, gas detection is one of the primary tools in the hazmat arsenal. When a team first enters a site, they typically use the "CROFT" methodology (Corrosive, Radiological, Oxygen, Flammable, and Toxic) to ensure the higher-end analyzers are not affected because of a lack of oxygen or a high pH level. Most teams then use a general survey tool such as a Photo Ionization Detector (PID) or Flame Ionization Detector (FID) to identify the presence of an unknown gas. These devices work by breaking the molecules present in the gases and then analyzing release ions--similar in principle to the smoke detector in your home.

Once the team has identified the presence of an unknown, a higher-end detection method (Fourier Transform Infrared Spectroscopy, Gas Chromatography, Mass Spectrometry) is used to help determine the exact substance.

When entering a confined space, such as a room, the primary need is to determine concentration of elements in the atmosphere. These can be explosive gases or nerve gases such as sarin. In this case, teams use an ion mobility spectrometer, which determines the exact airborne compounds in real time.

Features to Look For
The gas detectors themselves must be well suited for the dangers a hazmat team faces. The devices must be reliable--functioning properly all the time, every time--and they need to be easily maintained during "off duty" hours. Also, the devices must have intrinsic safety. That is, they must not create a hazardous situation in an already hazardous environment.

Of equal importance, these devices need to be portable. Most PIDs and FIDs are hand-held, and other higher-end analyzers can be mobile, either hand carried via a backpack or a wheeled case.

No matter how quickly they can be delivered to the scene, each device must be easily operated, particularly when responders are wearing turnout gear. As a result, size is always a factor. Too large is an obvious problem. Too small, and a first responder won't be able to read, or even handle, the device while wearing a Class A hazmat suit.

On-scene decision-makers have a different bias: accuracy. If a fire chief must decide whether to evacuate a building in the absence of clear visual evidence (such as a blazing building), they must make the decision using other reliable information. Lives are at stake in every step of a hazmat situation.

The last, vital feature for gas detection equipment is interoperability. In mutual aid situations, each group, whether firefighters, the Federal Emergency Management Agency, etc., needs to be able to use the same equipment. If these groups, possibly located in different states, are called to a scene, they need devices that are dependable and whose operation is covered in a shared standard operating procedure. Each first responder should be able to use any piece of equipment quickly and with little specialized on-site training.

The Vendor/Customer Partnership
When making any plan to buy gas detection devices, first responders must work closely with vendors. In the public sector, teams often know they need high-end equipment, but they may not know what the real needs are or which equipment might work best in which situations.

The vendor should help identify when it's appropriate to use a particular tool. Also, the vendor should provide best practices or methodologies for deployment in the field during an actual response. Vendors also should work closely with the teams to develop standard operation procedures or standard operation guides--if needed--to help in a response.

This collaboration creates a mutually beneficial relationship: The vendor imparts expertise with a particular technology and product, while the customer shares real-world experiences that will help improve the product. Ultimately, this exchange saves lives.

First response teams should always check vendor references. If a certain piece of gas detection equipment finds its way into the hands of the New York City Fire Department, for example, it must have all of the qualities first responders need and expect. But, more importantly, it must have been tested and proven in the field. Real-world use is the true acid test for gas detection instruments.

Of course, not all detectors make their way into the field for use by first responders. When the private sector opens its wallet, it typically buys for its industrial hygiene department for use in emergency response situations. Because of this, corporations typically plan for future needs, often by upgrading to the latest equipment sooner, rather than later.

What's Next?
And just what will the next generation of gas detectors offer? Newer analyzers give laboratory-grade results on the scene, leading to quicker and more accurate decisions. They will also be critical in compiling forensic evidence. When a compound is removed to a lab, not only is time lost, but also, physical properties of the substance could change. Completing the analysis at the scene eliminates this risk and conserves valuable time.

Even the latest and best equipment is ineffective if it is not in the hands of a skilled professional. This is the reason that the need for a comprehensive approach to hazmat situations, with dedicated and specially trained first responders, is increasing. When operated by well-trained experts, gas detectors can make the difference between success and deadly failure.

Arriving first on the scene of a disaster is both a curse and a blessing. First responders have the enormous responsibility of charging into the blaze, meltdown, or spill to save lives while placing their own in great danger. Often, they must combat unseen foes with the ability to kill instantly. But it's encouraging to know these individuals can march into these deadly situations armed with the best technology--proven in the field--and backed by the expertise of dedicated scientists and engineers. In an uncertain world, it's the closest thing to certainty first responders have.

This article originally appeared in the March 2003 issue of Occupational Health & Safety.

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