According to KWQC-TV6 on August 21st:

A gas leak forced students and staff to evacuate a Rock Falls elementary school Friday. According to district superintendent Dan Arickx, a construction project is going on behind Merrill Elementary School and crews hit an unmarked gas line.

The school implemented its crisis plan and students and staff were moved to a church across the street from the school building. Then, busses were brought in and transferred everyone to the middle school where parents were notified to come pick-up their children.

The gas line was eventually capped and staff members returned to the school to gather their items. They were then dismissed for the day.

Arickx says he is pleased with how the crisis plan worked and said everyone did what they needed to do quickly.