What is a sign that indicates a job site is clear?

Painting an "OK" in the dig extent clearly communicates that the area has been checked and is deemed clear for digging or excavation activities. This marking serves as a visual confirmation to all workers and personnel on site that the specific location is safe and ready for the next steps in the project. The use of an "OK" marking specifically indicates approval for proceeding, thus minimizing the risk of confusion or potential accidents associated with unmarked or unclear sites.

In contexts of site safety and communication, the clarity and recognition of such signals are crucial. By having a standardized marking like an "OK," all workers can easily understand the status of the dig extent without having to interpret different signals or flags that could lead to misunderstandings.