Chemical Safety: Chlorine Bombs and Algaecide Detonators

by Sean Griffin, April 30, 2009

 Chlorine Catastrophes and Algaecide Fires

         It’s every pool owner’s worst nightmare, turning your pool equipment into a ticking time bomb. Unfortunately the same chemicals used to sanitize your water can have an extremely adverse affect if applied improperly.  Chlorine has been used in chemical warfare since World War1 and is still present today as terrorists abroad are using chlorine gas in conjunction with conventional vehicle-borne explosive devices to cause severe damage. 
Chlorine fires burn extremely hot, and have melted warehouses in a few short hours. Our boss, Rob, has a story of a chlorine drum catching fire in the back of his service truck. "I was at a pool, in the back of my truck, needing a scoop for granular chlorine (shock). Finding none, I cut off the top of a Poly 60 algaecide bottle, and used it to scoop shock chlorine from the drum into a small bucket. Afterwards, I left the "scoop" in the drum of shock, with algaecide residue. 10 minutes later, from the corner of my eye, I had the hottest, meanest fire I could ever imagine. Water laughed at it! Dirt made it dance! I had to let it burn down - that truck was scarred for life!"
            Pool equipment along with pool chemicals stored in your backyard have the same harmful potential.   It is important to educate yourself on the proper application for your equipment and chemicals to avoid property damage and/or bodily injury. It is also wise to know what you should do if you have to deal with a chemical burn, chemical inhalation, or how to clean-up a chemical spill. keep your local poison control center and HAZMAT telephone numbers should be on hand in case of an emergency.
Reading labels on chemicals and equipment and following the manufacturers recommendations is a step no one can afford to skip. Follow all manufacturers label instructions. They are very clear and specific, by law.
Chlorinators along with brominators are at risk not only from water pressure but can combust if any added chemical does not have the proper time and space to expand due to off-gassing.  A relatively common mistake made by pool owners and sometimes even pool companies, is adding fast dissolving chlorine, calcium hypochlorite (granular) to a chemical feeder that is not designed to deal with the pressure increase. The result, you just turned your pool chlorinator into a bomb waiting to explode potentially sending plastic shards across your backyard. Chlorine/bromine pucks (Trichloro-Isocyanuate) are designed to slowly dissolve and are compatible with most chemical feeders.
Chlorine by its self can be hazardous along with other maintenance chemicals and specialty chemicals. The real danger occurs when chemicals are mixed and this should never be done.  Forms of chlorine mixed with acid can create mustard gas. Algaecide mixed with chlorine can become a home-made road flare.  Even chlorine mixed with acidic soda products can result in an expanding reaction. Antifreeze mixed with Chlorine reacts very strongly. Different types of chlorine should never be mixed. Don't mix granular with tablets. Don't mix Dichlor granular with Cal Hypo granular. Never mix chemicals!

Always refer to Material Safety Data Sheets (MSDS) for an in-depth look at the product you are using. For example…

EXTINGUISHING MEDIA: Carbon dioxide, water, water fog, dry chemical, chemical foam.
OTHER CONSIDERATIONS: Use water to cool fire-exposed containers and to protect personnel.
EXPLOSION HAZARDS: Product contains a flammable solvent. Vapors may be released that travel long distances
Remember the key in preventing accidents is taking your time, reading all labels, and following them.  Always store chemicals as recommended by manufacturer. Never mix chemicals and for your safety always have a plan in case a problem does occur.