OSHA has adopted a permissible exposure limit (PEL) of 0.75 ppm (parts per million) for airborne formaldehyde averaged over an 8-hour work shift (TWA). Formaldehyde can be smelled at less than 0.5 ppm. A short-term exposure limit (STEL) of 2 ppm for 15 minutes has also been established. For an assessment of airborne formaldehyde in the work area or lab, contact EH&S at 412-624-9505 via your supervisor or PI.