(b) Corrosives. Corrosive materials cause
caused by handling gloves, pencils, mixing cups,
tissue destruction without normal healing.
etc., that are contaminated with a toxic material after
removal of protective equipment.
(c) Sensitizers. Repeated exposure to a
2 Inhalation. Inhalation is the process
material that is a sensitizer may result in sensitization.
by which material is drawn into the body by breath-
Sensitization results in an allergic reaction either to the
ing. During mixing and layup of adhesives and patch
skin or in the respiratory system upon re-exposure to
materials, the release of solvents and other vapors
the material. Persons sensitized to a certain material
may occur. Inhalation of these materials cured lam-
can react strongly to trace amounts of that material
inates can generate composite dust. Inhalation of
upon re-exposure. Sensitized persons require zero
dust can be harmful to respiratory organs.
exposure to that material to prevent a repeat of the
a Total Dust. This refers to all the
(2) Chronic Toxicity. Chronic toxicity refers to
dust generated by an operation. Figure 2-1 shows a
the adverse health effects caused by exposure to a
comparison between the diameters of a typical human
toxic material over a long period of time. Chronic
hair (about 60 microns), the diameter of a carbon
toxicity testing is performed to determine a speciic
iber (about 7-9 microns) and the iltration size of
dose or exposure level that will produce a long-term
particulate trapped by a high eficiency particulate air
toxic effect. Some of these effects include blood
(HEPA) ilter (0.3 micron).
disease, liver damage, kidney damage and may have
carcinogenic (cancer producing) potential.
b Respirable Dust. Articles smaller
than about 10 microns in diameter are able to bypass
(a) Exposure Routes. During handling and
normal respiratory defenses and reach the deep lung
where they can cause respiratory damage. There
processing, toxic materials can enter the body through
are respirable exposure limits for some dusts, based
three main methods: direct contact, inhalation and
only on the fraction that is able to penetrate into the
1 Direct Contact. Direct contact with a
3 Ingestion. To ingest means literally
toxic material can result in surface damage to the
skin or eyes and internal damage to body organs
"to take into the body as food or liquid". While
if the material is absorbed. The areas of the body
it is doubtful that anyone would purposefully ingest
most susceptible to exposure are the unprotected
these materials, it is deinitely possible to ingest them
parts of the skin, such as the hands, lower arms and
accidentally. This commonly occurs via secondary
face. Skin or eye contact with liquids, gases, vapors
and particulate materials (dusts) should be minimized.
washing of hands prior to eating or drinking and
Special precautions should be taken to prevent contact
keeping food and drinks out of the work area provide
with chemicals absorbed through the skin. Direct
signiicant protection from accidental ingestion.
contact can also take the form of secondary exposure