Final answer:
The Short-Term Exposure Limit (STEL) is the exposure standard referring to the 15-minute Time Weighted Average limit that shouldn't be exceeded during a worker's day.
Step-by-step explanation:
The Short-Term Exposure Limit (STEL) refers to the 15-minute Time Weighted Average exposure which cannot be exceeded at any time during a workday. It provides guidelines to limit the exposure to hazardous substances in the short-term, to ensure that workers are not subject to excessive concentrations that could lead to adverse health effects. This contrasts with the Threshold Limit Value (TLV), which is more related to long-term exposure over a workday, the Ceiling Limit which must not be exceeded at any time, and the Time-Weighted Average (TWA) which is averaged over a typical 8-hour workday.