DCHAS-L Discussion List Archive
Date: Mon, 25 Jan 2010 09:31:52 -0500
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From: Kim Auletta <kauletta**At_Symbol_Here**NOTES.CC.SUNYSB.EDU>
Subject: Possible cause for this HS chem accident
I think I have a possible cause for this HS chemistry class accident. I
asked one of our researchers here who was a former food science chemist.
She said that it if the teacher used the SOUR flavor, they set up an
incompatible reaction.
Tartaric acid is used in the food industry to make the "sour" taste for
gums and candy. The JT Baker MSDS for potassium chlorate (
http://www.jtbaker.com/msds/englishhtml/P5620.htm) specifically lists
tartaric acid as an incompatible material:
Incompatibilities:
Iodides, tartaric acid, aluminum, sulfuric acid, hypophosphite, powdered
metals, organic matter and many other oxidizable substances.
It is also possible that all of the candy/gum wrapper was not removed and
the caused a more vigorous reaction than anticipated.
This experiment, which appears to be common in HS chemistry classes,
should have the following safety instructions included for all who
demonstrate this reaction:
1. Read the MSDS for all chemicals before you use them. Make sure to read
more than 1 manufacturer's MSDS - not all listed the specific chemical
incompatabilities.
2. Do not use the SOUR flavor for the candy.
3. Check all glassware for any nicks, scratches, etc. Do not use if
present.
4. Use a plexiglass or lexan shield between the students and the
demonstration.
These shields can be purchased from Fisher (cat.# 1429340), VWR, Flinn
(cat. #SE225) or other companies. They are expensive, but can be made
relatively cheaply - buy a large sheet of lexan or plexiglass 5 to 20 mm
thick and ask the Tech Teacher to cut it and mount it on a metal base.
Remember that the OSHA Lab Standard requires that there are written
protocols for all experiments. These protocols must include the safety
requirements!
Kim Auletta
Lab Safety Specialist
EH&S
Stony Brook University
kauletta**At_Symbol_Here**notes.cc.sunysb.edu
631-632-3032
EH&S Web site: http://www.stonybrook.edu/ehs/lab/
_____________________________________________________________________
New York
http://www.dailyfreeman.com/articles/2010/01/21/news/doc4b57e5a7a5748273921860.txt
Teacher recovering; cause of blast uncertain
Published: Thursday, January 21, 2010
By JAY BRAMAN JR.
Correspondent
BOICEVILLE — The explosion on Tuesday that injured an Onteora High School
chemistry teacher and seven of his students came as a surprise to
everyone, but probably no one more than the longtime teacher himself.
Donald Bucher was demonstrating an experiment with the chemical potassium
chlorate when the explosion — which was strong enough to damage a window
in the classroom — occurred. Onteora school district Superintendent Leslie
Ford said on Wednesday that Bucher had conducted the same experiment
dozens of times before, without incident, and that the cause of the
explosion remained a mystery.
Ford said Bucher was resting at home on Wednesday, recovering from his
injury, and that an investigation of the incident will begin shortly.
"We still don’t know what happened," the superintendent said. "But we will
debrief Mr. Bucher when he is well enough to return."
Ford said a small piece of glass punctured Bucher’s arm and cut an artery.
"He was bleeding quite a lot," she said.
A reporter’s calls to Bucher’s home were not answered on Wednesday.
The seven students who were injured, all 11th-graders, were treated at
Kingston and Benedictine hospitals, primarily for minor cuts, and
released.
Ford said the explosion occurred when Bucher dropped a stick of gum into a
test tube containing potassium chlorate, a chemical used in matches,
explosives, gunpowder and fireworks.
Ford said school district officials reviewed the chemistry class’ lesson
plan and concluded the experiment had been performed safely by Bucher in
the past. She also said it is a standard high school chemistry experiment
and that Bucher executed each of its steps properly on Wednesday.
"The goal of the experiment was to determine the amount of oxygen in the
potassium chlorate," Ford said.
The superintendent said possible causes of the accident were a faulty test
tube or the chemical itself being compromised.
All the remaining potassium chlorate in the classroom was removed, bagged
locked in a secure location elsewhere in the building by Michael O’Rourke
of the Risk Management Department at Ulster BOCES, Ford said.
O’Rourke said on Wednesday that the chemical will be disposed of properly
and other chemicals in the school will be checked for problems.
According to a Web site co-maintained by the National Oceanic and
Atmospheric Administration, potassium chlorate is a white crystalline
solid. It is used in matches, explosives, gunpowder and fireworks; as a
disinfectant; and as an oxidizing agent. It forms a flammable mixture with
combustible materials, and the mixture can be explosive if combustible
material is finely divided.
Potassium chlorate can be ignited by friction, and contact with strong
sulfuric acid may cause fires or explosions, according to the Web site.
Also, it may spontaneously decompose and ignite when mixed with ammonium
salts and may explode under prolonged exposure to heat or fire.
Ulster County Emergency Management Director Art Snyder appeared before the
Onterora Board of Education during the body’s regularly scheduled meeting
Tuesday evening. He outlined the procedures for hazardous materials
disposal, though Ford noted the procedures were not required in Tuesday’s
incident.
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