What is one of the hazards that must be checked on a work site before operating an excavator?

Checking for overhead service lines is critical before operating an excavator due to the potential hazards they present. Overhead power lines, communication cables, and other utilities can create significant risks if contact occurs during excavation activities. The machinery's height and the operator's line of sight might obstruct visibility, leading to the danger of electrocution or damaging essential infrastructure. Ensuring that these lines are identified and properly marked allows operators to maintain a safe distance and implement precautionary measures to prevent accidents.

While the other factors may also be relevant to overall site safety, they do not pose the immediate and significant risk associated with working near overhead service lines, which can lead to severe injuries or fatalities. Recognizing and mitigating the dangers associated with overhead lines is a fundamental safety practice in excavation work.