ON SEPTEMBER 15, 2014, a high school chemistry teacher in Colorado intended to demonstrate the characteristic emission spectra of metal ions with a flame test large enough for the
entire classroom to watch. The different colored flames produce the so-called rainbow effect,
which would certainly impress the students. Unfortunately, in this instance, four students were
injured. All four suffered burns, one seriously.
Methanol flame tests
are typically performed
by placing 5 to 7 grams
of a metal chloride in a
glass Petri dish and then
adding 7 to 10 milliliters
(mL) of methanol. After
turning down the lights,
the instructor lights the
mixture, and the class
observes the flame test color. But demonstrators are cautioned not to add more methanol
to the Petri dish after starting the demonstration—the mistake this teacher made.
The flame quickly traveled back up into the
bottle and ignited the rest of the methanol. Pressure built up within the bottle, as the temperature
of the gases produced in this chemical reaction
quickly increased, and the bottle spewed a fiery
stream of methanol at a distance of 12 feet ( 3. 6
meters), hitting a student in the chest.
In September and October 2014, a total
of 22 students and two adults were injured
throughout the United States in four separate
incidents involving methanol used in rainbow
demonstrations.
Could these accidents have been prevented? Where can teachers (and students)
find the type of information needed to use
chemicals in a safe and responsible fashion?
Fortunately, there is a system in place to provide ready access to this type of information.
Every chemical has its own Safety Data
Sheet (SDS), formerly known as a Material
Safety Data Sheet (MSDS), containing a
wealth of information in a simple, easy-to-read
format. Especially prominent
within each SDS are safety
precautions needed to han-
dle the chemical properly,
as well as any potential
health hazards. A L A
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Safety Data Sheets
Information that
By Brian Rohrig
Understanding the
hazards of chemicals
If you ever read the labels of chemical products, you may have noticed a lot of symbols.
The use of these symbols is a direct result
of recent efforts to modernize and standardize the way chemicals’ potential hazards
are labeled. One update is the adoption of a
uniform set of pictograms developed by the
United Nations, which is used throughout
the world. Quiz yourself on p. 6 to see
if you can match these symbols with
their warnings.
An SDS meets the requirements of the
Occupational Safety and Health Administration (OSHA), a U.S. federal agency created
to ensure a safe work environment for all
employees. OSHA mandates that all workers
exposed to chemicals have the right to know
about the potential hazards of these chemicals.
Could Save Your Life
When conducting a flame
test, soaking wooden
splints in salt solutions
and then placing the
splints in a Bunsen burner
is considered a safer
alternative than working
directly with flammable
liquids, such as methanol,
which is not recommended
anymore.
