What does the Permissible Exposure Limit (PEL) mean?

Unless noted otherwise PELs are time weighted average (TWA) concentrations of a substance that must not be exceeded during any 8-hour work shift of a 40 hour week.

If the measurement of a chemical is less than the PEL is further monitoring needed?
Other measurement factors that should be considered are:

The short term exposure limit (STEL) which is the maximum concentration of exposure to a substance over a 15-minute period.

Immediately dangerous to life or health (IDLH) is the maximum concentration from which, in the event of a respirator failure, one could escape within thirty minutes without a respirator and without experiencing any escape-impairing or irreversible health effects.

Do not forget that monitoring for the PEL, STEL and IDLH criteria pertains to the inhalation of dusts, gases, vapors, mists or fumes only. Dermal exposure assessments or protection could also be necessary.

What options are available when interfacing with a routine work place hazard?
When addressing a work place hazard the first step should be to engineer out the concern. If the hazard cannot be removed then it should be reduced and isolated. Administrative work shift changes can also be implemented. The last response should be to keep the hazard and use personal protective equipment (PPE).

Can any worker wear a company assigned respirator?
When a hazard cannot be engineered out of the work place and a respirator is necessary the OSHA 1910.134 respiratory protection standard must be met. Some of what is included is a medical exam and a physicians written opinion that a respirator can be worn by a specific individual. In addition a respirator fit test to ensure that proper fit is achieved.

Is respiratory protection necessary when saw cutting concrete, granite countertops, roof tiles and concrete blocks?
Reducing concrete to a powder and making it airborne can pose a risk to those that are exposed. Inhalation of concrete dust can result in crystalline silica exposure. This can lead to a disease known as silicosis. Wetting the blade at the point of contact will minimize the dust levels and the wearing of an appropriate particulate filtering respirator is recommended.