What is the term for the fire protection method in which townspeople formed two lines to pass containers filled with water toward the fire and empty containers away from it?

Answer: The terminology bucket brigade is a technique for transportation of items where items; passed from one person to the next. The method was crucial in firefighting ahead the arrival of pumped fire engines, whereby firefighters would pass buckets to each other to extinguish a flame.

Therefore the correct term for the given question is bucket brigade.