What is the Threshold Limit Value (TLV) STEL for a chemical?

The Threshold Limit Value (TLV) STEL (Short-Term Exposure Limit) is defined as the maximum concentration of a chemical to which workers can be exposed for a short period of time, typically around 15 minutes, without suffering from adverse health effects. This value is specifically designed to reflect conditions that can occur over a short duration during the workday.

The correct answer reflects that the concentration can be exceeded for brief periods (usually not more than four times per day) as long as the average exposure over an 8-hour period does not exceed the established TLV for that chemical. This allows for flexibility in exposure without compromising worker safety, acknowledging that short bursts of higher exposure may be tolerable if they do not occur too frequently or exceed limits set for longer-term exposure.

In contrast, answers related to maximum concentration during longer exposure durations or specific hour limits do not accurately define the STEL, highlighting its unique role in occupational safety for short-term exposures.