Hazardous material decontamination operators await the arrival of contaminated patients of a mock nuclear attack during Operation Vibrant Response. Muscatatuck Urban Training Center is the Army's premier urban warfare training site in Butlerville Indiana. (DoD photo by Benjamin Faske) Date	8 November 2009, 10:39 Source	091108-F-8594F-797 Author	US Air Force from USA
19 Feb 2024

Ammonia, chlorine, chlorine dioxide and hydrofluoric acid the most common chemicals involved in HazMat accidents


What to train for in HazMat? Large or small? The high impact, rare incident or the more likely incidents?    

HazMat resources, both in terms of training time and equipment, are to some degree very limited for all firefighters, regardless of size. You could perhaps never train well enough to handle some extremely rare, yet possible, high impact incidents. 

So how do you best spend your HazMat resources and training time? 

As HazMat Nation argues in their February 8th article, smart teams spend most of their training time for those events that are more likely to happen, with less, but still consequential outcomes.

In September 2023, Axios.com searched through 20 years of U.S. Environmental Protection Agency data and determined which were the three most common chemicals in HazMat incidents, or as parts of other incidents.

Ammonia Ammonia: Often present at meat packing plants and food processing plants in refrigeration systems. Very dangerous when released. 

According to AICHE.org, the Dakar accident in Senegal, West Africa, 1992, is the worst industrial accident involving ammonia in terms of fatalities:  Anhydrous ammonia, which was used to detoxify the product made at the facility, was stored in a portable tank commissioned in 1983 and repaired via welding in 1991. The weld repairs were made on cracks detected on the tank’s surface. An overpressure inside the tank led to its catastrophic failure, releasing 22 m.t. of pressurized ammonia.

41 people died immediately, and many others were transported to the nearest trauma center. Ultimately, the incident caused 129 fatalities and 1,150 injuries.

More recently, in  May 2023, CNN covered some of the severe health problems experienced by workers and where one worker died at a food plant when exposed to ammonia.


Chlorine and chlorine dioxide: The second most common in chemical accidents, according to the study. Used to disinfect and sanitize water, to process sewage and to handle industrial waste. The deadliest chlorine accident in the United States is the Graniteville freight train derailment  (CTIF.org Jan 15 2018) where 9 people died and 500 people were injured.  

More recently, two dozen people were hospitalized in connection to a chlorine gas leak at a facility run by the Olin Corporation near Baton Rouge, Louisiana. 


Hydrofluoric acid is the third most common in chemical accidents, according to the Environmental Protection Agency records: Used to make refrigerants, herbicides and pharmaceuticals.Also used in oil refineries.

According to the CDC (Centers for Disease Control and Prevention) it can irritate the eyes, nose, and respiratory tract. 

However: The French government agency database ARIA defined Hydroflouric acids as possibly "the worst of all acids" in their News Flash from 2015. 

Despite being produced 200 times less than sulphuric acid (1 M vs. 200 M tonnes/year), the ARIA database has recorded nearly 80 accidents involving hydrofluoric acid (HF) (vs. 220 for H2 SO4 ). A series of recent accidents serves to recall its hazards, especially the serious consequences in the event of its release.


BBC: 8 tonnes of hydrofluoric acid was discharged into the atmosphere via a tanker truck on September 27, 2012 in Gumi, South Korea: The tanker was transporting 20 tonnes of 98% HF which was undergoing transfer by two technicians.  The leak killed five facility employees instantly, and another 18 were injured from inhalation and had to be hospitalized. 

In the near vicinity, a total of 4,195 individuals were treated in hospital. Regionally, 12000 people had to be medically examined, according to Aria's Newsflash. 

416 firefighters were treated for nausea, skin rashes, breathing difficulties and irritations, according to the Aria newsflash. 

The incident reportedly contaminated 212 hectares of land and 3,900 cattle had to be slaughtered. 80 plants were shut down due to the release, 1200 vehicles were corroded and 91000 tonnes of vegetation was burned. 

Download the Aria News Flash to read about South Korea's "Ammonia Disaster" in Gumi


Highly corrosive: It dissolves the majority of minerals (oxides, silicates), metals and plastics. 

Higly toxic • : Fluoride ions F- penetrate deeper tissue layers and fully react with both magnesium and calcium. The resulting salts formed are thus toxic for living cells.. 

Higly soluble in water • : The acid reacts violently with water (releases smoke) and cannot be distinguished from it. 

Weak acid • : For concentrations of <40%, a chemical burn on the skin is not painful at first, but only once the bone has been reached. It is felt several hours later. 

Potential fuel source • : Despite being non-flammable, HF in solution reacts with lightweight alkaline metals in releasing hydrogen (H2:an extremely flammable and explosive gas).


Photo Credit: This image or file is a work of a U.S. Air Force Airman or employee, taken or made as part of that person's official duties. As a work of the U.S. federal government, the image or file is in the public domain in the United States.

Hazardous material decontamination operators await the arrival of contaminated patients of a mock nuclear attack during Operation Vibrant Response. Muscatatuck Urban Training Center is the Army's premier urban warfare training site in Butlerville Indiana. (DoD photo by Benjamin Faske)

Date:  8 November 2009, 10:39

Source: 091108-F-8594F-797

Author : US Air Force