Cold Planers & Milling Machines

Cold planers (milling machines) grind off the top layer of asphalt or concrete pavement with a spinning drum fitted with carbide teeth, and load the material onto trucks by conveyor. They work beside live traffic with ground crews close by. The drum, the conveyor, dust and the trucks all create serious hazards.

• Milling Operators
• Road Crews
• Truck Drivers
• Flaggers & Grade Checkers

Main hazards

• Rotating drum and teeth: contact can amputate or kill. Teeth can break and be thrown. Parts stay hot after use.
• Struck-by and run-over: milling machines and trucks move around ground crews, who are often behind or beside them. Operators have blind spots. See Backing & Spotters and Struck-By & Caught-Between.
• Traffic: work zones next to live lanes. See Work Zones and Road Construction.
• Silica and dust: milling asphalt and concrete creates respirable dust, which may contain silica. See Silica and Dust Control Methods.
• Asphalt fumes, heat and hot material: milled material can be hot, and fumes can irritate. See Asphalt Paving.
• Noise and vibration from the drum and engine. See Noise.
• Conveyor hazards: pinch and nip points, and falling or flying material. See Conveyors.
• Utility and structure strikes: manholes, valve boxes, utility lines and shallow cables can be hit, damaging equipment and workers. See Utility Strikes.
• Falls on and off the machine, and slips on wet or dusty steps.

Operating safely

• Only trained, authorized operators run the machine, with a pre-use inspection of the drum, teeth, guards, conveyor, water system, brakes, steering, lights and alarms. See Operator Training & Evaluation.
• Wear high-visibility clothing, hard hat, eye and hearing protection and sturdy boots. See High-Visibility Clothing.
• Keep guards and covers in place around the drum housing and drives. Never run the machine with a guard removed.
• Use a seat belt where fitted and a three-point grip on steps. Don't ride on the machine as a passenger.
• Follow the traffic control plan and don't enter live lanes without protection. Keep a safe distance from passing vehicles.
• Use the horn and backup alarm, and use a spotter when backing or in tight areas. Keep trucks and the planer a safe distance apart.
• Know where utilities, manholes and drainage are before milling, and mark them. Slow down and lift the drum over covers as the plan says.

Ground crew safety

• Stay out of the machine's path, especially behind it, near the drum and in front of the conveyor and truck. Keep eye contact with the operator before approaching.
• Never walk or stand between the planer and a haul truck or between the planer and barriers. Use designated safe zones.
• Grade checkers and survey crews should work from agreed positions and signals, and use radios. Don't cross the cut area during operation.
• Wear high-visibility gear and keep to a plan for where each person works. Use proximity detection where available. See Proximity Warning Systems.
• Use the water system and dust controls and wear respirators if monitoring or the plan requires them. See Respiratory Protection.

Changing teeth and maintenance

• Stop the machine, lock out and tag out, and lower and block the drum or use the drum lock before changing teeth or working in the drum chamber. See Blocking & Cribbing.
• Let the drum and teeth cool, and wear gloves and eye protection. Teeth can be sharp and hot.
• Use the right tools, such as tooth removal tools and hammers, and watch out for flying fragments. Keep others away.
• Depressurize hydraulics before servicing, and check for leaks. See Hydraulic Hazards.
• Keep the machine clean of asphalt buildup and fuel, and carry fire extinguishers. See Equipment Fueling.
• Follow a transport plan for moving the planer on a trailer. See Equipment Loading & Trailers.

Cold planer checklist

• I'm trained, inspected the machine and kept all guards in place
• A traffic control plan and spotters are in use; ground crew stay out of the path
• Nobody walks between the planer and a haul truck
• Water, dust control and respirators are used as planned; utilities are marked
• I lock out and block the drum before changing teeth or servicing

Last updated: October 5, 2026