Mechanic in a heavy-truck repair bay putting a red safety padlock on the truck's battery disconnect switch.

Regulations & Standards

Chock, Lock, Verify: Energy Control for Vehicle and Mobile-Equipment Repair

November 11, 20268 min read

By Riley M.

Short answer: Before anyone works under or between a vehicle or mobile equipment, immobilize it (park, set the brake, chock the wheels, lower or block raised parts), lock out every energy source, including the starting circuit and stored hydraulic and air pressure, then verify it can't start or move. Turning the key off isn't lockout.

The space under a truck, loader or trailer is a crush zone. A vehicle doesn't need a driver to move: a starter that turns over, a transmission left in gear, a slope, a hydraulic arm that drifts down or an air system that bleeds off can all do it. Turning the key off isn't lockout. Before anyone goes under or between, the vehicle has to be immobilized, its energy has to be controlled, and someone has to verify both.

Our lock-out/tag-out guide covers fixed machinery. This post is the follow-up for vehicles and mobile equipment.

What happened in Montreal

On November 4, 2026, Quebec's CNESST published its findings on the death of a Cintas Canada worker in Montreal on April 10, 2026. According to CNESST, the worker was under a heavy vehicle in the company yard, diagnosing a no-start, and positioned in the path of the front right wheel. He connected the starter solenoid terminals. That powered the starter while bypassing the vehicle's normal controls and the safety devices that usually prevent starting unless the transmission is in Park or Neutral. The transmission was in Drive, and no immobilization measure, such as wheel chocks, was in place. The vehicle lurched forward and pinned him between the wheel and the ground.

CNESST found two causes: the worker powered the starter by bridging the solenoid terminals from under the vehicle, and no energy-control method was in place for work under the vehicle. In CNESST's words (our translation), the accident could have been avoided "in particular if an energy-control method applicable to mobile equipment had been developed and applied."

An Ontario reminder: anything that can move has to be secured

On November 10, 2026, Ontario's Ministry of Labour, Immigration, Training and Skills Development reported a $50,000 fine against Essex Weld Solutions Ltd. after a worker in Leamington was critically injured. He was adjusting a mobile roller conveyor made of four sections, each about 430 pounds. While he was loosening the bolts joining the sections, the conveyor collapsed. The company pleaded guilty to failing to ensure the conveyor was securely blocked against tipping during maintenance, contrary to section 46 of O. Reg. 851 (Industrial Establishments). The court also added a 25% victim fine surcharge.

That case involved a conveyor, not a vehicle, but the lesson carries straight over to the shop floor: gravity is energy too, and anything that can tip, roll or drop has to be secured before work starts.

Where the energy hides in a vehicle

CCOHS defines hazardous energy as "any electrical, mechanical, hydraulic, pneumatic, chemical, nuclear, thermal, gravitational, or other energy that can harm personnel" (CCOHS, Hazardous Energy Control Programs, citing CSA Z460-20). On a vehicle or piece of mobile equipment, that can mean:

Electrical: the battery and starter circuit.
Hydraulic: dump bodies, booms, lift arms, tailgates and brake systems.
Pneumatic: air brakes and air suspension.
Gravitational: raised bodies, buckets, forks or blades, and any vehicle parked on a slope.
Mechanical: springs and anything else under tension.

CCOHS also makes a point every shop should take to heart: lockout and hazardous energy control are not the same thing. Lockout is one method. Where lockout alone can't get equipment to a zero-energy state, other controls are used, including blocks, chocks, pins, bars, chains or cribbing. The same isolate-first thinking applies before anyone enters a tank or pit, which our confined-space air testing and rescue checklist covers.

Chock, lock, verify

Build these steps into a written procedure for each piece of mobile equipment, following the manufacturer's instructions.

1. Chock: immobilize it.

Park on level ground where possible, put the transmission in the position the manufacturer specifies, and set the parking brake.
Chock the wheels.
Lower forks, buckets, blades and bodies, or block them solidly before anyone works under them. Never rely on hydraulics alone to hold a raised load over a person.

2. Lock: control every energy source.

Remove the key and keep it with the person doing the work.
Isolate the starting circuit the way the manufacturer specifies, for example at the battery or battery disconnect, and lock it out where a lockout point exists.

Red ABUS 00457 universal forklift and plug lockout device, a hinged clamshell cover with Danger Do Not Operate labels and padlock holes

Release or block stored hydraulic and air pressure per the manufacturer's procedure.
When more than one person is working on the same unit, use group lockout so every worker has their own lock on.

Red ABUS 72/40 TITALIUM aluminum lockout padlock

3. Verify: prove it before you go under.

With everyone clear of the crush zone, confirm through your written procedure that the vehicle can't start or move and that raised parts are blocked.
Never bypass a safety interlock to troubleshoot from under a vehicle. If diagnostic work needs power, follow the manufacturer's procedure and keep everyone out of the path of the wheels and moving parts.

CNESST's prevention advice lines up with this: develop, document and apply an energy-control procedure specific to each piece of mobile equipment; inform workers of the risks and train them on those procedures; follow the manufacturer's recommendations and procedures; and keep workers out of areas where unexpected movement could pin, crush or strike them. In a busy yard, high-visibility clothing helps drivers see anyone on foot near a moving unit.

What Ontario's rules say

For industrial establishments, O. Reg. 851 requires that:

machinery, equipment or material that may tip or fall be secured against tipping or falling (s. 46);
a vehicle left unattended be immobilized and secured against accidental movement (s. 57);
machinery, equipment or material that is temporarily elevated, where a worker may pass or work under it, be securely and solidly blocked (s. 74);
maintenance or repair be done only when dangerous motion has stopped and parts that could move have been blocked (s. 75); and
where starting a machine or device may endanger a worker, its controls be locked out and other effective precautions taken to prevent starting (s. 76).

Construction projects, mines and federally regulated workplaces have their own regulations, so check the one that applies to your shop. Getting this right is a big part of why safety matters on every crew, and crush hazards from moving equipment belong on any list of common workplace hazards.

Keyline Safety's stand

Turning the key off isn't lockout. Before anyone works under or between vehicles or mobile equipment, the unit should be immobilized and every energy source controlled under a written, equipment-specific procedure that the crew has been trained on. Then someone verifies it before anyone goes in. If a job seems to need a shortcut, like bridging a starter from underneath, the procedure needs fixing, not bypassing.

What Keyline Safety does

We supply the lockout hardware that a vehicle and mobile-equipment energy-control program runs on, including our range of ABUS safety products:

Our Lockout / Tagout collection, including the ABUS Universal Forklift / Plug Lockout 00457. Its listing covers electric-forklift battery plugs, the starter battery negative (-) terminal, and the LP cylinder shut-off valve on propane forklifts.
Personal locks and hasps: ABUS 72/40 TITALIUM aluminum padlocks and ABUS H701 to H712 steel lockout hasps, so every worker can put on their own lock.
Group lockout: the ABUS Portable Group Lockout Box B835 and the ABUS 12 Lock Lockout Station 71150 for keeping locks organized at the shop.
Cable lockout: the ABUS C553 Standard Cable Lockout for isolation points that a single lock can't reach.

Worker placing a key into a red ABUS group lockout box mounted on equipment, with several coloured lockout padlocks attached

Building or updating a lockout program for your shop? Contact Keyline Safety through our safety assistant chat, and we'll help you choose the lockout devices that fit your equipment.

Frequently asked questions

Is turning off the ignition enough before working under a vehicle?

No. The vehicle also has to be immobilized, every energy source controlled and locked out where possible, and the result verified before anyone goes under.

What energy sources does a vehicle have?

Electrical (battery and starter), hydraulic (bodies, booms, lift arms), pneumatic (air brakes and suspension), gravitational (raised parts, slopes) and mechanical (springs and tension).

What does Ontario require for blocking raised equipment?

Under Reg. 851, machinery or equipment that is temporarily elevated, where a worker may pass or work under it, must be securely and solidly blocked (s. 74).