Illustrated Guide to Home Chemistry Experiments

Chapter 4: Chemicals for the Home Chemistry Lab 55

CEMICALH ALLERGIES

Some people are allergic to substances that are generally

considered to be “safe.” For example, some people react

very badly to the latex used in some protective gloves.

Before an allergic reaction can occur, you must be

exposed at least once to the allergen, but the number

of exposures required before an allergic reaction results

is unpredictable. For example, I knew a man who was

convinced he was immune to poison ivy. He’d handled it

with bare hands dozens of times over more than 20 years,

and had never had the slightest reaction to it. Until one

day he did.

Contact allergies are particularly problematic in a

chem lab, and for that reason you should wear gloves

when handling any chemical, even one that is generally

considered benign and that you have handled many times

before with no adverse reaction. Otherwise, the next time

you handle it you may regret not wearing gloves.

z

Storage Code notes

White: Corrosive. May harm skin, eyes, and mucous membranes. Store separately from flammable and

combustible materials.

Yellow: Oxidizing and/or reactive. May react violently with air, water, or other substances. Store separately from

flammable and combustible materials.

Red: Flammable. Store separately only with other flammable reagents.

Blue: Toxic. Hazardous to health if inhaled, ingested, or absorbed through skin. Store separately in secured area.

Green: Presents no more than moderate hazard in any of categories above; use general chemical storage.

Gray: Presents no more than moderate hazard in any of categories above; use general chemical storage. (Used

by Fisher Scientific instead of green.)

Orange: Presents no more than moderate hazard in any of categories above; use general chemical storage.

(Obsolete color code; superseded by green.)

Stripes: A reagent that is incompatible with other reagents of the same storage code color; store separately.

The storage color code system devised by J. T. Baker and
shown in Table 4-3 has become an industry standard. This
system assigns each chemical one of five storage color codes,
with or without a stripe, which indicates the primary storage
consideration for that chemical.

In theory, a chemical with a particular color code can safely be
stored with other chemicals that have the same color code. In
practice, there are many exceptions to that rule. For example,
although both sulfuric acid and sodium hydroxide may be coded
white for corrosive, that does not mean that they can be safely
stored together. Strong acids and strong bases must be stored
separately from each other.

A chemical that has a striped color code requires
individual consideration, and often must be stored separately
from other chemicals. For example, many suppliers color-
code sodium, potassium, calcium and other alkali metals
and alkaline-earth metals red with a stripe. The red indicates
that the metal is flammable, and the stripe indicates that
special storage requirements apply. (In this case, the metals
must be kept away from liquid water, with which they react
violently.) Similarly, some suppliers color-code strong mineral
acids white (corrosive) and strong bases white (corrosive)
with a stripe to indicate special storage considerations
(in this case, that they must be stored separately
from acids).

Furthermore, the color code assigned to a chemical indicates

only the primary storage consideration for that chemical. For

example, a chemical coded yellow (oxidizer/reactant) may also be

quite toxic (blue), while a chemical coded white (corrosive) may

TABLE 4-3: J. T. Baker storage color codes

SToRAGE CoLoR CodES