Forklift Carbon Monoxide Levels

Emissions Safety

As the weather cools, companies become diligent about keeping heating costs down. Doors, windows and vents are closed and air exchanges systems are shut down. However, production continues to run for the forklifts. When equipment is propane powered, carbon monoxide levels can build inside the warehouse or office area.

Carbon monoxide (CO) is a colorless, odorless, tasteless and non-irritating gas. Even low exposures to this gas can affect an employee, diminishing the blood’s capability to deliver oxygen to the body and vital organs. Concentration levels in the human body build slowly over time exposure continues, resulting in carbon monoxide poisoning.


It’s easy to forget propane powered forklifts produce carbon monoxide gas because the output is normally very low. However, the levels can be greatly affected by dirty air filters, engines needing tuning and fuel systems requiring service or adjustment. The age of a forklift also matters. An older forklift – no matter how well tuned and serviced – produces higher output percentages compared to a newer forklift’s engine.

A recent model of a propane powered forklift will produce as low as .5% CO exhaust gas concentration when tested at its tailpipe. This results in 5,000 Parts per Million (PPM). If the forklift is an older model or poorly maintained, the tailpipe output percentage could be as high as 2-4%. This output would produce CO levels at 20,000 – 40,000 PPM. A tremendous air exchange would have to occur to keep the CO levels within OSHA compliance.

OSHA CFR 1910 states CO exposure levels cannot exceed 50 Parts per Million (PPM) over a Time-Weighted Average (T.W.A.) for an 8-hour period. This level refers to the air within the building, not the CO percentage coming out of the forklift’s tailpipe. If the warehouse or facility is small or doesn’t have sufficient air exchange for the number of operating lifts trucks, illegal T.W.A. levels may be reached.


When a person visits a hospital and a blood gas test shows CO poisoning, the hospital is required to report the findings. An OSHA officer may visit later with PPM meters to hang in the facility. Later, the officer would return to review PPM over a T.W.A of 8 hours. High levels are subject to a written citation and compliance schedule to fix the problem quickly.

If carbon monoxide levels are suspected to be high, take precautions to lower the levels, including:

  • Ensuring air exchange is occurring within the warehouse and office area
  • Replacement of older propane powered forklifts for newer models
  • Placing forklifts on a regular maintenance schedule, ensuring tuning and service is administered
  • Looking for underlying causes of CO that may not be related to the forklifts.

Concerned your forklifts are outputting high levels of CO? Contact us to discuss servicing your equipment or placing it on planned maintenance.

Got Questions?

If you have a question on this or any topic related to safety with your forklift, give our resident expert, Dave Bennet, a call or fill out the request form.