Station Pride Articles

Officers…Ask These Questions at a Hazardous Material Incident

Author: Frank Docimo

As a fire officer you have been given the responsibility under the law to understand, guide and direct a hazardous material emergency. 29 CFR 1910.120(q) as well as HAZMAT IC training requirements under Federal, OSHA and NFPA 472 address the minimum training requirement for anyone commanding a hazardous material incident. The law states: IC’s who will assume control of the incident beyond the first responder awareness level shall receive at least 24 hours of training equal to the first responder operations level.

Considering the complexity of a chemical emergency, and the spilt second decision making, that has to be done during the incident, the IC needs a simple system that will guide them throughout the incident. Ask the following questions:

  • What is the product?
  • How will the product hurt me?
  • Is there enough product to hurt me?

With these three questions answered the IC can begin to gain control of the situation. However, even prior to answering these three questions, the IC’s first consideration should be the safety and security of the site. Once control zones have been established and assessment begins, the IC can address the three questions.

What is the product involved?

As a fire officer you should be very comfortable with the various types of clues that can be used to identify the presence of a hazardous materials. While developed for first responders who may not immediately recognize the of the presence of a Hazardous Materials release, the National Fire Academy’s program “Recognizing and Identifying Hazardous Materials” is an invaluable tool for first responders at any level of certification as it provides six clues for identifying hazardous materials:

  • Occupancy And Location
  • Container Shapes And Size
  • Marking And Colors
  • Placards And Labels
  • Shipping Papers/SDS Sheets
  • Your Senses

How will the product hurt first responders, the public, or me?

For the purposes of this article we will look at the type of harm that can occur right now. OSHA has defined three types of harm that can affect you immediately:

  • Flammability
  • Oxygen Deficient Atmospheres
  • Toxic Environments

As an IC you should be very familiar with the harm that can occur from fire. Flash point is the minimum temperature of a liquid at which it gives off sufficient vapors to form an ignitable mixture; fire point the lowest temperature of a liquid at which vapors are evolved fast enough to support continuous combustion and auto ignition temperature the minimum temperature to which a substance must be raised in order to ignite must be considered.

The next consideration in a flammable atmosphere is the concentration of the vapors. Remember, in order to have a fire, an atmosphere must have a minimum amount of fuel to air ratio. This minimum amount of product in air is called the Lower Explosive Limit (LEL). The LEL of a vapor or gas; is the lowest concentration that will produce a flash fire when an ignition source is present. At concentrations lower than the LEL, the mixture is too “lean” to burn. This is your first goal post. If we have a minimum amount of vapor in air, then we can also have a maximum amount of vapor in air. The Upper Explosive Limit (UEL) of a vapor or gas is the highest concentration that will produce a flash of fire when an ignition source is present. At higher concentrations, the mixture is too “rich” to burn. The UEL is the second goal post. This area between the two goal posts is the flammable range. Keep in mind that products with wide flammable ranges and low LELs present the greatest danger.

The second type of harm that can occur is an oxygen deficient atmosphere. In air the normal amount of oxygen is 21%. This percentage can be increased or decreased to levels that can cause immediate harm. Products with high vapor pressures and high expansion ratios will force the oxygen out and create an oxygen deficient atmosphere. Under OSHA law, if an atmosphere’s oxygen has been reduced down to 19.5% this is considered Immediate Dangerous to Life and Health (IDLH). At this level a self-contained breathing apparatus MUST BE WORN.

The third consideration is the toxicity of the product. IC’s should consider exposure routes:

Inhalation Hazard

Skin By Contact Hazard

Skin By Absorption

One of the fastest ways to toxify an emergency responder is by inhalation. The inhalation of a product can occur remote from the spill area and affect all of the responders (remember that everyone must breath). In all chemical emergencies it is critical that self contained breathing apparatus be worn at all times. Skin contact and skin by absorption present a different type of conditions. Skin by contact usually happens when someone gets to close to the chemical. This might happen prior to your arrival (as in a citizen exposure) or may involve one of your crew that has come in contact with the spilled material. In the case of skin by absorption, certain products can be lethal when absorbed through the skin.

Is there ENOUGH of the product released to hurt me? 

This third question is multifaceted:

In what concentration does the product exists?

Or is there enough product to cause harm?

Truly the only definitive way to answer this question is through the proper use of air monitoring equipment.

In the discussion of concentration we could classify these atmospheres as:



Dangerous Atmospheres

Many responders today will want a definition of “What is Safe” and argue that all chemicals in a high concentration or over long periods of time will eventually do some harm. Safe concentrations can be found in chemicals that are being used in their intended manor, possibly emitting vapors that are below toxic levels that various agencies have established, below 20% of the products LEL, or has not affected the amount of oxygen concentration in air.

Unsafe atmospheres can happen when an emergency exists and if there is a potential threat of release or actual chemical spills you may be in an unsafe atmosphere. It is very difficult to recognize or identify the unsafe atmospheres without a meter.

We tend to make general assumptions as emergency responders, if it’s spilled assume that it is Unsafe. Unsafe atmospheres may dictate the isolation of an area, some form of respiratory protection, or type of chemical protective clothing. Chemicals that are fast actors or deliver debilitating injuries can generate unsafe atmospheres quickly. Exceed any of the recommended levels established by various agencies; you are no longer safe! Whenever you are exposed to levels of chemicals above the Ceiling, Permissible Exposure Limits, or Recommended Exposure Limits (OSHA, NIOSH, ACGIH) it must be assumed that you are in an unsafe exposure, stay in it long enough and some form of harm will occur. Flammable atmospheres that have been monitored and have moved above 20% of the LEL uncorrected must be considered unsafe. Unsafe atmospheres must be treated with the utmost respect. Until adequate monitoring has been accomplished the emergency responder must assume that at the very least, there could be an unhealthy or unsafe exposure. IC’s and first responders must be very cautious under these conditions and exercise extreme caution.  Are you entering a suspected or known IDLH without a proper meter to perform a rescue or to shut off a valve?

Dangerous atmospheres occur when concentrations begin to exceed the “safe” levels and a potential for life threatening injuries can occur.  These high concentrations of any chemical are extremely dangerous to the responder’s Life and Health. This level is defined as Immediate Dangerous to Life and Health (IDLH). IDLH is as the maximum concentration that poses a threat for, immediate death, or immediate injury or permanent adverse health effects. It is established as a limit so that a worker could escape without symptoms that would impair one’s ability to escape. The symptoms that would retard escape are — 1) Blindness, 2) Unconsciousness, and 3) impaired judgment. In general, this value although limited and conservative is a value that represents the maximum concentration workers could escape if their respiratory protection fails.

Many chemicals possess dual IDLH values: Toxic / Flammability. In the case of some chemicals, when a chemical has reached its LEL it may be well above its (toxic) IDLH value.  As any responder knows we need 21% oxygen to carry on normal activities. When this concentration drops, our ability to survive diminishes.   Below 19.5% responders experience impaired judgment; the first affected organ is the brain.  Remember, oxygen contents below 19.5% are considered IDLH.

Will a simple system work when dealing with the complexity of a chemical emergency? Armed with the answers to these questions:

  • What is the product involved?
  • How will the product hurt my personnel the public or me?
  • And is there enough of the product there to hurt me?

You, the officer / IC can make knowledgeable decisions that will favorably change the outcome of an incident.

-Frank Docimo has been affiliated with the fire service for over 45 years, serving both his local community, Stamford, CT as well as a nationally recognized Hazmat instructor. During his career he has held the position of Special Operations Officer for the Turn of River Fire Department assigned to HAZMAT 1 in the City of Stamford, Connecticut. Docimo has also served as a subject matter expert working with the National Fire Academy, FEMA and the Bureau of Justice on a joint workshop entitled Emergency Response to Terrorism. Providing guidance on decontamination and risk assessment that is now part of their core curriculum. Frank Docimo is the creator and co-author of “Hazmaps 911: A Reference Guide for Common Hazmat Chemicals”

About Mutual Aid (43 Articles)
Station-Pride is committed to providing high-quality content for our viewers. In order to do so, sometimes our contributors just aren't enough. This profile has been created to request mutual aid from other writers and authors in the fire service who are willing to share their knowledge with our followers. Please keep an eye out for guest contributions, and some with anonymous authors. Please keep in mind, Station-Pride contributors hold themselves to a very high level of professionalism. With that being said, these articles are un-edited and viewer discretion is advised.

Thanks for leaving a comment on!

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: