Workbook for Designated Substance Assessments
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366-BPV-01-IMOT © 2024, Workplace Safety & Prevention Services (WSPS)
1 877 494 WSPS (9777) | 905 614 1400 | WSPS.CA
ASSESSMENT – WALK THROUGH SURVEY
A walk through survey is required to confirm the information gathered to date about the process and
worker's potential exposure.
A number of points should be noted about walk through surveys.
Note 1
The presence of the substance as dust or spilled liquid in the working environment, either airborne or
on working surfaces or workers' clothing, is an indication of potential exposure. Careful attention should
also be paid to any fumes, mists or vapours; and to any particular smells that indicate the presence of the
substance in the environment. Note, however, that smell is a poor test for evidence of over exposure as
many gases cannot be smelled even when they are above recommended safe limits.
Note 2
The time at which the survey is conducted should be carefully chosen. The survey should be done at a
time of typical activity involving the substance. Special note should be made of any times of peak activity
and how often these occur. However, it may be necessary to make several trips at different times in order
to observe conditions, at different shift times, or during different activities. A visit during lunchtime
might be useful for comparative purposes.
Note 3
Make sure that supervisors and workers are aware of the purpose of the walk-through. Make a note
of any information provided by supervisors or workers while conducting the survey. The following
worksheets will help you decide what to look for and what to record during a walk-through survey.
Note 4
Look everywhere and at everything that may be relevant. Ask lots of questions. Make notes on everything
you see and hear, including reported health effects.
Note 5
In general, you need to consider all the Ontario Regulations that apply to your workplace. For example,
the Ontario Regulation 851 Industrial Establishments, to evaluate compliance as well, especially in Part
III Industrial Hygiene, which states the requirements for the need of an eye wash.
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