1-12. THE PHASES OF INDUSTRIAL HYGIENE
The industrial hygiene programs, with which you will come into contact, will
normally consist of three phases previously mentioned: recognition, evaluation, and
control. These phases will assist you to reduce those environment factors that detract
from employee well being and to create a better work environment or physical and
physiological work environment.
a. Recognition. Health hazards in the work area must first be recognized. This
will usually be the result of the various surveys, inspections, and inventories, which you
will make. It can also result from listening to complaints received from workers or by
noting trends reflected in written reports.
b. Evaluation. The hazards present in the work environment must be evaluated
in terms of their long term, as well as their short term, effects on employees' health.
This evaluation will be based on all data available, from inspections and surveys, as
well as from experience and your technical knowledge.
c. Control. The last phase is the development, implementation, and follow- up
on corrective measures that will reduce or eliminate the existing health hazards.
Control measures may include:
(1) Replacement. Replacement of toxic or harmful substances with less
(2) Modification. Modification of work processes or procedures to minimize
or eliminate worker exposure.
(3) Ventilation. Utilization of ventilation to reduce the concentration of
harmful substances to safe levels.
(4) Distance. Increasing the distance between the worker and the source of
the harmful substance or the noise.
Protection. Requiring the use of personal protective equipment or
(6) Isolation. Isolation of a process of work operation to reduce the number
of persons exposed.
(7) Wet methods. Using wet methods to reduce emission of dusts to the
atmosphere such as in the case of abrasive blasting, lathing, and grinding operations.
(8) Housekeeping and cleanliness. Good housekeeping, including
cleanliness of the work place; proper waste disposal; adequate washing, toilet, and rest
room facilities; healthful drinking water and eating facilities; and control of insects and