Threshold Quantity (TQ)

Definition:
Threshold Quantity (TQ) is a legal term from U.S. regulations. It refers to the amount of hazardous chemical at a facility that triggers regulatory requirements such as OSHA PSM or EPA RMP.

Key Points:

  • Exceeding TQ mandates full compliance with regulations.
  • Different substances have different thresholds.
  • Generally, PSM and RMP are aligned in what TQ is for the same chemical. They make it easy that way.
  • Facilities may try VERY HARD to not exceed these values by limiting their operations and even their profits.

Example:
Threshold quantity for anhydrous ammonia under PSM is 10,000 pounds.

See Also: PSM, RMP

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