If a tank mix of Products A and B was applied and Product A has a restricted entry interval of 12 hours and Product B has a restricted entry interval of 18 hours, how long must a worker wait until going back into the treated area if not wearing the appropriate PPE?

• A. 6 hours
• B. 12 hours
• C. 18 hours
• D. 30 hours

Answer: (C)

When entering a treated area, you must respect the restricted entry interval (REI) for the products used. In a tank mix, the entry time is determined by the longest REI among all products in the mix, because you could be exposed to residues from the product with the longer interval. Here, Product B has the longer REI of 18 hours, and you’re not wearing the appropriate PPE, so you must wait 18 hours before re-entering. The shorter 12-hour REI for Product A is superseded by the longer 18-hour requirement. Therefore, 18 hours is the correct wait time.