| |
attributed to certain occupations since the fourth century
B.C. The occupational health effects of mining toxic
metals, such as lead and mercury, were studied and well
documented in 1473. Then in the early 20th century, the
U.S. Public Health Service and U.S. Bureau of Mines
conducted the first detailed federal studies on worker
health. This concern for worker health and safety
progressed slowly until 1970, when Congress passed the
Occupational Safety and Health Act (OSHA). Industrial
hygiene, as a profession, has been around for several
hundred years, but didn’t become a specialty within the
Navy until the 1940s.
Industrial hygiene is both a science and an art; it
concerns the total realm of control of the work
environment. This realm of control includes recognition
and detailed evaluation of workplace environmental
factors that may cause illness, lack of well being, or
discomfort among workers. Using this information, the
industrial hygienist formulates recommendations to
alleviate safety and health problems.
When speaking of the work environment, we
include the following factors:
Lighting
Ventilation
Air contaminants
Facility design
Physical stressors (heat, humidity, vibration,
noise, radiation)
Safety hazards (flying chips, turning shafts, saw
blades)
INDUSTRIAL HYGIENE SURVEYS
An industrial hygiene survey involves inspecting
every workplace at the facility or ship, from the
overhead to the deck. Inspectors observe work processes
and document all potential hazards. To quantify these
hazards, inspectors take readings with meters and other
types of equipment. They also collect air samples for
laboratory analysis (fig. 5-1). They measure noise with
a sound level meter. They use small air pumps to collect
dust, vapors, or gases to determine exact exposure
levels. These exposure levels help determine the hazard
to workers and what controls are required. Controls are
then tailored to the facility or workplace to eliminate or
lessen the hazard. These controls generally fall into
three categories:
Engineering controls (design) and substitution
Administrative controls (e.g., stay times)
Use of personal protective equipment (PPE)
An industrial hygiene officer, civilian industrial
hygienist, or industrial hygiene technician conducts the
survey. Medical clinics, environmental and preventive
medicine units, destroyer tenders, and submarine
tenders provide industrial hygiene support.
INDUSTRIAL HYGIENE TERMINOLOGY
The following are some of the units and terms you
will see on workplace monitoring and industrial hygiene
survey reports:
Action level–Unless otherwise specified in a
NAVOSH standard, one-half the relevant
permissible exposure level (PEL) or threshold
limit value (TLV).
Ceiling limit (C)–The maximum hazard
exposure concentration level, expressed as
TLV(C), at which a person may work.
Concentration–The quantity of a substance per
unit volume (in appropriate units). The following
are examples of concentration units:
mg/m3–milligrams per cubic meter for
vapors, gases, fumes, or dusts.
ppm–parts per million for vapors or gases.
fibers/cc–fibers per cubic centimeter for
asbestos.
Decibel (dB)–A unit used to express sound
pressure levels; specifically, 20 times the
logarithm of the ratio of the measured sound
pressure to a reference quantity of 20 micro-
pascals (0.0002 microbars). In hearing testing,
the unit used to express hearing threshold levels
as referred to audiometric zero.
Permissible exposure limit (PEL)–The legally
established time-weighted average (TWA)
concentration or ceiling concentration of a
contaminant or the exposure level of a hamlful
physical agent that must not be exceeded.
Short-term exposure level (STEL)–The con-
centration to which workers can be exposed
continuously for a short time without suffering
from (1) irritation, (2) chronic or irreversible
tissue damage, or (3) narcosis.
5-3
|
