Chapter 4: Chemicals for the Home Chemistry Lab 49Exposure Controls/Personal Protection
Physical and Chemical Properties
Stability and Reactivity
Toxicological Information
Ecological Information
Disposal Considerations
Transport Information
Regulatory Information
Other InformationMost laboratory supply houses publish an MSDS for each
chemical they carry, or at least for each chemical that presents
any significant hazard. The MSDS may be produced by the vendor
or by the company that actually made the chemical.
The MSDS should be your primary source of safety information
about each chemical you buy. If no MSDS is provided, search
the Web for an MSDS for that chemical. Read the MSDS for
every chemical, even those that present no special hazard.
Print a copy of the MSDS for each chemical that presents a
significant hazard, and file it in your laboratory binder. Decide
conservatively which MSDS sheets to print. For example,
although you probably don’t need a printed copy of the MSDS
for sodium bicarbonate or even ethanol, you probably should
keep printed copies of the MSDS sheets for strong acids and
bases, oxidizers, and poisons.
nPA 704 FF IRE DIAMOnD
The NFPA (National Fire Protection Association) rates
various chemicals to identify the specific types and degrees
of risks they present to firefighters and other emergency
personnel. Rated chemicals are assigned an NFPA 704 fire
diamond. The fire diamond helps emergency personnel
quickly and easily to identify special procedures, precautions,
and equipment necessary to minimize the danger the
chemical presents.
S of oIx NE...
An MSDS produced for a particular chemical by one
supplier may have minor differences from the MSDS
for the same chemical from another supplier, but for
our purposes they can be considered interchangeable.
For example, if you purchase potassium permanganate
crystals from a pet supply store that doesn’t provide
an MSDS, you can use the potassium permanganate
MSDS from J. T. Baker, Mallinckrodt, Fisher Scientific, or
some other supplier. Just be sure that the MSDS refers
to exactly the same chemical and in the same form and
concentration. For example, an MSDS for dilute nitric acid
is very different from an MSDS for fuming nitric acid.The four sections of the fire diamond specify
the type of risk in four categories: health
(left), flammability (top), reactivity (right), and
special codes for unique hazards (bottom).
The three top sections contain a number from
zero to four that specifies the degree of that
risk. The bottom section may contain a symbol that represents
the unique danger, if any. Although it is not required, the four
sections of the NFPA 704 fire diamond are usually color-coded.Health (Blue)- Very short exposure may cause death or major residual injury
(e.g., hydrogen cyanide gas) - Short exposure may cause serious temporary or residual
injury (e.g., carbon tetrachloride) - Intense or continued but not chronic exposure may cause
temporary incapacitation or possible residual injury (e.g.,
pyridine) - Exposure may cause irritation but only minor residual injury
(e.g., potassium carbonate) - Exposure offers no hazard beyond that of ordinary
combustible material (e.g., sodium chloride)
Flammability (Red)- Rapidly or completely vaporizes at normal temperature
and pressure or is readily dispersed and will burn readily
(e.g., butane gas, magnesium dust) - Can be ignited at normal ambient temperatures
(e.g., gasoline) - Must be moderately heated or exposed to relatively high
ambient temperatures before ignition occurs (e.g., fuel oil) - Must be preheated before ignition can occur (e.g., olive oil)
- Not flammable (e.g., calcium carbonate)
Reactivity (Yellow)- Readily detonates or explosively decomposes at normal
temperature and pressure (e.g., nitroglycerin) - May detonate or explosively decompose from a strong
initiating force or severe shock, if heated under confinement,
or in contact with water (e.g., benzoyl peroxide) - Undergoes violent chemical change at high temperature and
pressure, reacts violently with water, or may form explosive
mixture with water (e.g., phosphorus) - Normally stable, but may become unstable at high
temperature and pressure (e.g., calcium metal) - Normally stable even when exposed to fire and is not reactive
with water (e.g., boric acid)
Special Hazard (White)
W or WATER – Reacts with water in an unusual or dangerous
manner (e.g., sodium metal)
OX or OXY – oxidizer (e.g., potassium permanganate)31
0