The human respiratory system, and its association with the
circulatory system, represents the most direct route of toxic
entry into the body. This section will list and briefly describe
respiratory hazards and the type of respirator necessary for
the specific contaminant which may be encountered. Proper
hazard control should start at the engineering and design
level and should include 1) substitution of a less harmful
material or substance for a toxic one; 2) isolation or encapsulation
of the process; and 3) ventilation of the contaminant before
the worker is exposed. Hazards can be classified as follows:
- Gas
and vapor contaminants
- Oxygen
deficiency:
Immediately dangerous to life or health (IDLH)
Not immediately dangerous to life or health
- Particulate
contaminants (dust, fog, fume, vapor, mist, smoke, and spray)
- Combination
of gas, vapor, and particulate contaminants.
CAL/OSHA - General Industry Safety Order 5141 - Requires prevention
of worker exposure to harmful levels of airborne contaminants.
OSHA Standard 1910.134. States that respirators shall be selected
on the basis of the hazards to which workers are exposed, and
that ANSI Z88.2- 1969 shall be used for guidance in their selection.
For specific respiratory hazards, specific instructions for
respiratory selection are given in other OSHA regulations (e.g.,
Asbestos, 1910.1001). The trend is toward regulations that are
specific to the contaminant in question. OSHA has a new standards
list called the Respiratory Selection Guide which is very useful
for this type of application.
Class 1 - Air purifying devices
The air purifying device cleans the contaminated atmosphere.
This device is limited in its use to those environments where
there is sufficient oxygen to sustain life. This is strictly
a device meant as a source of diluting air that is relatively
contaminant free.
- A.
Mechanical-filter respirators - These offer respiratory
protection against airborne particulate matter, including
dust, mist, metal fumes, and smoke. The NIOSH certifies
mechanical filter respirators under subpart K of title 30
CFR, part II.
B.
Chemical cartridge respirators - These are used to protect
against concentrations between 10 and 1,000 ppm (parts per
million) depending on the contaminant. These respirators
are not to be used in IDLH environments. Note: Responsibility
for testing respirators for agricultural chemicals belongs
to NIOSH-MSHA (Title 30, CFR, part II, subpart M). Approved
combination type units for pesticides are now available.
C.
Gas masks - These are used for respiratory protection
against certain gases, vapors, and particulate matter that
otherwise may be harmful to life or health. It is important
to note that their use should be restricted to atmospheres
which contain sufficient oxygen to support life. Gas masks
should be used for escape only from IDLH atmospheres, but
never for entry into such environments. Note: If a specific
exposure is expected to exceed an allowable limitation,
only a self contained breathing apparatus (SCBA) should
be used.
Class 2
- Atmosphere- or air-supplying devices
This is a class of respirators that provides a respirable atmosphere
independent of the ambient air.
- A.
Self Contained Breathing Apparatus (SCBA) This provides
complete respiratory protection against toxic gases or an
oxygen deficient environment. The user of this type of respirator
is independent of the surrounding atmosphere because he
or she is breathing with a portable system that admits no
outside air. The apparatus provides the air supply.
Class 3
- Combination air purifying and atmosphere supplying devices
This device is a combination of an air-line respirator with
an auxiliary air-purifying attachment, which provides protection
in the event that air supply fails. The most popular versions
are those in which the air purifying element is a high efficiency
filter. This filter is approved for dusts, fumes, and mists
that have a permissible exposure limit (PEL) of less than 0.05mg/m3.
CAL/OSHA Respiratory Protection Program GISO 5144. This document
summarizes the basic components of a respiratory protection
program. To properly use any respiratory protective device,
it is essential that the operator be properly instructed in
its use. OSHA requires that employees be trained in the use
of the particular respirator assigned to them.
Many companies have their employees sign a document attesting
to their having completed a training session.
The OSHA regulation lists several tenets of a respiratory protection
program. The key element of any program starts with an assessment
of the inhalation hazards present in the workplace. This initial
step involves gathering the necessary toxicological, safety,
and research data on the substances in the atmosphere. A simple
questionnaire can be obtained to assist in gathering the pertinent
information about the exposure conditions.
Disclaimer and Reproduction Information: Information in
NASD does not represent NIOSH policy. Information included in
NASD appears by permission of the author and/or copyright holder.
More
