Heather --

This question comes up fairly frequently in fire museums. . . . And on the Museum-L (see archives)

The earliest grenade-type fire extinguishers were invented in the late 1800s. They were designed to be thrown at the flames where the glass would break and the contents would spill out. Made of clear or colored glass, these early extinguishers usually have a fancy cut-glass, round or octagonal shaped body, and a tall neck and usually contained a HARMLESS salt water and brine solution. "Harden" or "Hayward" were the most common brand names.

On the other hand, the smaller glass "light bulbed" shaped grenades (such as the one mentioned in this original post), were made from 1920 to 1960s and they DO contain "Carbon Tetrachloride." These extinguishers were usually red in color (or with red liquid inside), and usually carried the brand names of either "Red Comet," or "Shure-Stop." Some hung on a wall or sat in a box and were designed to be thrown at the flames, while others incorporated a fuse and spring and worked much like a modern sprinkler head. When exposed to high-heat (flames) a small piece of soft metal would melt, releasing a spring, breaking the glass, and dispersing the contents. Also made during the 1920s through 1960s were numerous size and shaped models of metal (usually brass) fire extinguishers that also contained Carbon Tetrachloride as the firefighting agent. The most common was the “Fyer-Fyter” brand and was a small handheld brass cylinder (somewhat like a large sausage stuffer) that had a piston-pump plunger handle on one end and a small nozzle on the other.

Questions about what do with these extinguishers (and their contents) have been raised a number of times. Should an extinguisher be emptied? How dangerous are the contents? What should be done with them? What happens if one breaks?

While carbon-tet IS classified as a HAZARDOUS MATERIAL, (and is banned from production). Although chemical is believed to be a carcinogen that can be inhaled and absorbed though the skin, the most significant danger comes only when the chemical reacts with heat/fire. Under intense heat, carbon-tet forms toxic fumes (phosgen-gas) that smother the flames and deprive the air of oxygen. Although I have never heard of someone becoming ill because of a recent leak/spill, I would use caution when storing or displaying these items. If the glass has remained intact all these years, it is recommended you leave it alone, I have never found a way to “drill” and drain the contents, though others claim they have.

Some of the "light bulbed shaped" glass extinguishers have a spring release mechanism that automatically breaks the. If you find one of these, I would recommend you should secure/disable that spring release to prevent accidental breakage. When dealing with the other (metal) fire extinguishers with carbon-tet, it is advisable to empty the contents by emptying them outside (under the direction of your local fire department or hazardous materials team) in a WELL ventilated.

If an extinguisher (with carbon-tet) does accidentally break/leak, the “proper” response would be to leave the room and ventilate the area. Your fire department can assist you with providing large fans to help with the ventilation process, but carbon-tet evaporates and disperses quite quickly (probably before they get there in typical two to three minute response time). After the fumes subside, any residual liquid (and the glass fragments) can be wiped up using rubber gloves and paper towels or absorbent pads.

Although carbon-tet IS indeed dangerous, if you respect the extinguisher and its contents, and with a little caution and common sense steps taken to prevent accidental breakage or release, you should be safe.

- David -
David Lewis, Curator
Aurora Regional Fire Museum
and the Fire Museum Network's Web Guy
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* DISCLAIMER -- I am not a chemist nor do I want to play one here on the Internet, (I nearly failed chemistry in High School). My comments are based on personal experience in dealing with a carbon-tet leak, talking with others, consulting with our local hazardous materials response team, culled from various posts to the Fire Museum Network Discussion Board, and common sense.

We have come across 2 red comet Fire Extinguishers (one c. 1940 and one c.

1920) while unpacking our collection and they are still filled with what is

most likely carbon tetrachloride.  Any advice on how other institutions have

handled disposal/display/storage/replication of these?  



Thanks!

Heather





--

Heather Pozun Watson

Director, Fremont Co. Pioneer Museum

1443 W. Main Street

Lander, WY 82520

Ph: 307-332-3373

Fax: 1-866-899-2534

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