Nothing about an extension cord suggets danager. There are no moving parts, no flames, and no noise. It is harmless looking, yet it can be extremly dangerous if misused. No extension cord can stand roug usage. If you kink it, knot it, or crush it, you can break the insulation, which may cause a short cirucit, fire, or even an electric shock. Most cords used carry regular 110-volt electricity. At some point, you may have received a shock from a 110 volt line without serious harm, but even a 10-volt current can seriously injury or kill if the conditions are right with wet or sweaty hands, or a wet floor or water pipe are a few examples. Never let an extension cord sit in water.
Inspect all extension cords at the beginning of each workday for any signs of wear or damage. Remove any worn/damaged cords from service immediately.
If there are cuts in the outer jacket, or insulation, or wiring, or the ground is missing that means the cord needs to be taken out of service.
Handle the cord genlty, avoiding strain, kinking, crushing, or cutting.