Another possibility is that the demo involved molten potassium chlorate – also known as the gummy bear immolation demonstration. A small piece of candy, such as a gummy bear is dropped into molten potassium chlorate - a dramatic red flame (that can sho ot out several inches from the reaction) immediately is produced via the sugar in the candy reacting with the oxygen in the molten KClO4 and the flame heatin g the K+ ions. Afterwards, everything in the immediate area is covered with K Cl. I’ve done this one several times in the past, but always in evaporati ng dishes, never out of a test tube. Nowadays, I would never do this in a classroom.

I think I have a possible cause for this HS chemistry class acciden t. I asked one of our researchers here who was a former food science chemist. Sh e said that it if the teacher used the SOUR flavor, they set up an incompatib le reaction.

Ta rtaric acid is used in the food industry to make the "sour" taste for gu ms and candy. The JT Baker MSDS for potassium chlorate (http://www.jtbaker.co m/msds/englishhtml/P5620.htm) specifical ly lists tartaric acid as an incompatible material:

Incompa tibilities:
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.

Th is experiment, which appears to be common in HS chemistry classes, should have the following safety instructions included for all who demonstrate this reactio n:

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 incompatabilitie s.
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.

Th ese shields can be purchased from Fisher (cat.# 1429340), VWR, Flin n (cat. #SE225) or other companies. They are expensive, but ca n 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.

Re member that the OSHA Lab Standard requires that there are written protocols for al l 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/

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New York

http://www.d ailyfreeman.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 chemist ry teacher and seven of his students came as a surprise to everyone, but proba bly no one more than the longtime teacher himself.

Donald Bucher was demonstrating an experimen t 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 condu cted 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 Wedn esday, recovering from his injury, an d that an investigation of the incident will begin shortly.

“We still don’t know what happened,” the superintendent said. “But we will debrief Mr. Bu cher 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 h ome 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.< br>
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 prop erly on Wednesday.

“The goal of the experiment was to det ermine the amount of oxygen in the potassium chlorate,” Ford said.

The superintendent said possible causes of t he accident were a faulty test tube or the chemical itself being compromised.< /font>

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 Uls ter BOCES, Ford said.

O’Rourke said on Wednesday that the ch emical will be disposed of properly and other chemicals in the school will be chec ked 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 firewor ks; as a disinfectant; and as an oxidizing agent. It forms a flammable mixture with combustible materials, and the mixture can be explosive if combustible mate rial is finely divided.

Potassium chlorate can be ignited by frictio n, 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 body̵ 7;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.