The primary method for the protection of laboratory
personnel from hazardous airborne contaminants should be to minimize the
amount of such materials entering the laboratory air. When effective engineering
controls (such as fume hoods and local exhausts) are not possible, suitable
respiratory protection must be provided.
In the absence of a fume hood or other adequate engineering
controls, masks and monitoring are required; there is a definite sequence
that must (by law) be followed:
- Persons who will be in contact with the chemical(s)
must be identified.
- Monitoring must be done to determine if exposure
to the chemical(s) exceeds 50% of the Threshold Limit Value (TLV) or the
Permissible exposure Limit (PEL), whichever value is more stringent.
- If monitoring indicates exposure above allowed levels,
persons identified above must be sent for medical evaluations to be sure
that they do not have a physical condition that would be aggravated by
the use of a mask (medical screening).
- Such persons must then be provided with masks specifically
designed to protect against the chemical(s) in question.
- Each person for whom a mask has been ordered must
be fitted and trained in its use.
(Please note that the "surgeon's masks" available
from hardware stores and various Harvard stockrooms are not made to protect
the user and are not sufficient to protect against hazardous chemicals.)
Call the Safety Office (5-7478) for help in obtaining monitoring, medical evaluation, fitting, and training.