WORKER EXPOSURE ASSESSMENTS

When must an employer conduct an exposure assessment? When you expose your employees to a respiratory hazard and/or require them to wear respirators. Examples of when you should consider assessments may include but are not limited to:
When OSHA has a substance specific standard (e.g., lead, methylene chloride).
When employees notice symptoms (e.g., irritation, odor) or complain of respiratory health effects.
When the workplace contains visible emissions (e.g., fumes, dust, aerosols).
<source: https://www.osha.gov/SLTC/etools/respiratory/change_schedule_exposure.html>