What 29 CFR 1926.453 requires (plain English)
29 CFR 1926.453 governs aerial lifts in construction: vehicle-mounted, boom-supported elevating work platforms such as boom lifts, bucket trucks, and articulating and telescoping aerial devices. These machines lift workers high into the air, often near electrical lines and over hard surfaces, so tip-overs, falls from the basket, and ejection ("catapulting") are the primary hazards. The standard sets the fall protection, positioning, and operating rules that keep an aerial lift from becoming a fatal fall.
The core fall-protection rule is specific: a body belt (or, in current practice, a full-body harness) must be worn and a lanyard attached to the boom or basket when working from an aerial lift. The attachment point is the lift's own boom or basket, not an adjacent structure, so the worker moves with the machine. Workers must always stand firmly on the floor of the basket and must not sit or climb on the edge of the basket, and must not use planks, ladders, or other devices to gain extra height inside the basket. These rules prevent both falls and the ejection that occurs when a basket lurches.
Operating discipline completes the standard. Lift controls must be tested each day prior to use to make sure they function safely, and the manufacturer's load and operating limits (boom and basket load limits, allowable positions) must not be exceeded. Because aerial lifts frequently work near power lines, they must maintain safe clearance from energized lines, and only authorized, trained persons may operate them. A distinctive point: scissor lifts are NOT aerial lifts, OSHA regulates them as mobile scaffolds under Subpart L (1926.451/452), so the aerial-lift rules of 1926.453 do not apply to them.