Many
departments on campus have the occasion to use apparatus that produce
ultraviolet radiation. This
management procedure should be used as a guide so that necessary precaution
will be taken to avoid UV radiation exposure.
Ultraviolet
(UV) radiation is an invisible radiant energy produced naturally by
the sun, and artificially by arcs operating at high temperatures. Artificial sources commonly found on campus
include germicidal and black light lamps, carbon arcs, welding and cutting
torches, electric arc furnaces, and other laboratory equipment.
Since
the eyes and skin readily absorb UV radiation, they are particularly
vulnerable to injury. The severity
of radiation injury depends on factors which include exposure time,
intensity of the radiation source, distance from the source, wavelength,
sensitivity of the individual, and presence of sensitizing agents.
Sunburn
is a common example of the effect of UV radiation on the skin. Since UV radiation is not visible, the person
exposed to UV may not be aware of the hazard at the time of exposure.
Absorption
of the radiation by the mucous membranes of the eye and eyelids can
cause conjunctivitis. Lesions
may also be formed on the cornea at high exposure levels.
Such injuries usually manifest themselves 6 to 12 hours after
exposure.
Protective
measures are essential for persons exposed to high intensity UV sources. Goggles, face shields, and masks provide protection
for the eyes; protective clothing and barrier creams minimize skin exposure.
Shiny metal surfaces reflect UV radiation, and, when possible,
should be removed from the work area. Reflections from lamp housings, walls, ceilings,
and other surfaces may be reduced by coating these surfaces with a pigmented
paint to low UV reflectance. Very
high levels of UV should be enclosed, so as to shield those in the area.
Exposure
to UV may be a cause of skin cancer.
The following facts are known concerning UV radiation carcinogenesis:*
1. The incidence and prevalence of skin cancer correlate with decreasing
geographic latitude, hence with the degree of insulation.
2. Over 90% of skin cancers occur in parts of the body exposed to
sunlight.
3. The amount of pigmentation affects the incidence and prevalence
of skin cancers.
4. Skin cancer is more prevalent in people who spend more time out
of doors.
At
this time, the relationship between UV radiation and the incidence of
skin cancer is inconclusive. However,
many studies substantiate the
hypothesis
that exposure to UV is related to the development of skin cancer.
*NIOSH
Technical Report "Carcinogenic Properties of Ionizing and Nonionizing
Radiation. Volume 1 - Optical
Radiation."