Is it Bad to Inhale Fire Extinguisher Residue Dust?

Recently, I spoke with a lady who had the unfortunate experience of a kitchen fire occurring in her home. Luckily for her, they had a portable fire extinguisher in the kitchen and knew how to use it.

After the fire, they were faced with the issue of safely cleaning up the fire extinguisher residue. One such question was the dangers of inhaling the fire extinguisher residue dust.

So, is it bad to inhale fire extinguisher residue dust? Moderately yes. The dry chemical powder in standard ABC class fire extinguishers and others will irritate the respiratory system if it is inhaled making breathing difficult.

Before you go calling an extremely expensive cleaning crew to come in and clean up the extinguishing powder, it would be helpful to know what type of fire extinguisher was used to extinguish the fire and what personal protective equipment (PPE) is needed to clean up the mess yourself. 

The Type of Fire Extinguisher Used Matters

There are different types of fire extinguishers on the market today. An understanding of the different types of fire extinguishers and the agents used to extinguish the fires is important. This information will help determine the level of harm that could be experienced if exposure to the agent occurs, as well as the best methods for proper cleanup.

Class ABC Fire Extinguishers

This is the most common fire extinguisher on the market, used in both residential and commercial settings. The extinguishing agent used is monoammonium phosphate. Monoammonium phosphate is considered an irritant to the respiratory system and therefore indicates that you should use proper personal protective equipment to protect yourself during clean up.

Class BC Fire Extinguishers

Designed to extinguish Class B and Class C fires, the BC fire extinguishers use Sodium Bicarbonate as their extinguishing agent. The agent is in a powder form and can also irritate the respiratory system if exposure occurs and you do not have the proper personal protective equipment.

Class K (Purple K) Fire Extinguishers

Class K fire extinguishers use a blend of potassium acetate and potassium citrate forming what is known as a potassium bicarbonate-based agent. This too is a dry chemical powder and will irritate the respiratory system if exposure results you do not have the proper personal protective equipment.

Halotron and Carbon Dioxide Fire Extinguishers

Halotron I and II, and Carbon Dioxide fire extinguishers are designed to be used on sensitive electrical equipment and are known “clean agent” fire extinguishers. They are known as “clean agent” extinguishers because they leave no residue/powder behind after the fire extinguisher has been discharged in suppressing the fire, but rather the agent dissipates into the air and no clean-up process is required. The residue of other discharged fire extinguishers can corrode and damage sensitive electrical equipment and are therefore not recommended for use on these types of fires.

How to Safely Clean Up After Using a Fire Extinguisher

If you have discharged a dry chemical fire extinguisher and are now preparing to engage in the clean up process, read our other article titled, “How to Safely Clean Up Dry Chemical Fire Extinguisher Residue”.  The article details the steps and guidelines to properly and safely clean up the residue powder left behind from the extinguishment, as well as the necessary Personal Protective Equipment that may be recommended to protect yourselves from inhaling the powder, or from experiencing exposure to your skin or eyes.