Injuries associated with poorly-functioning, propane-powered forklift trucks are reported extensively in occupational health literature. 

In a well-functioning, propane-powered forklift truck, fuel combustion produces water vapour and carbon dioxide. But, when the fuel mix is incorrect, particulates and carbon monoxide (an odourless gas that is taken up preferentially by haemoglobin in the blood) can be produced instead. The risks associated with this can range from headaches, dizziness and nausea to acute carbon monoxide poisoning[1].

Incidents of carbon monoxide poisoning associated with LPG-powered forklifts in industrial settings were highlighted in a 1999 report by the United States Centers for Disease Control and Prevention[2]. The report set out a number of occasions where employees regularly suffered the first signs of carbon monoxide poisoning.

Up to half of those who suffer severe carbon monoxide poisoning are thought to experience long-term neurological or psychiatric symptoms. These symptoms can fall into three categories - changes in behaviour, movement (motor abnormalities), and memory or thinking (cognitive dysfunction).

When speaking to a forklift truck worker who experienced severe carbon monoxide exposure, he told me that he didn’t recognise the symptoms mentioned above, but he did report feeling “down”, experiencing higher levels of anxiety than previously and severe fatigue.

This is unsurprising given a case control study[3] of the neurological consequences of carbon monoxide poisoning found while there was no difference between groups when cognition was tested, patients who had experienced carbon monoxide poisoning did have a lower quality of life, were more depressed than those who had not been exposed to carbon monoxide and suffered more from post-traumatic stress disorder. They also showed significantly lower cognitive performance on processing speed, mental flexibility, inhibition, and working and verbal episodic memories. The prognosis of symptoms resulting from carbon monoxide poisoning are not well documented.

Due to the high frequency of injuries associated with using an LPG-fuelled forklift indoors, in the United States, it is considered good practice for employees to be trained to recognise the symptoms associated with carbon monoxide poisoning.

Unfortunately, the Health and Safety Executive in the UK seem less concerned with these dangers. They provide only the briefest of warnings in the rather unhelpfully titled COSHH (Control of Substances Hazardous to Health) SR14[4] and this devotes just one line to the subject: “Test LPG ­fuelled engines for carbon monoxide emissions regularly”.


In light of the clear evidence of the danger of serious injury associated with poorly-maintained propane forklift trucks and inadequately ventilated premises where such vehicles are used, we urge employers to make themselves aware of the risks – and ensure their workers are aware, too.

David Coulthard Accident at work specialist


Thompsons Solicitors wants employers to take safety seriously. They have a legal duty of care to protect their employees in the workplace. This includes preventing or reducing workers’ exposure to hazardous substances at work and complying with the COSHH Regulations 2002.

We launched our ‘Under the COSHH’ campaign to help employees understand whether their employer has a robust health and safety structure in place to protect them and their colleagues. Our Under the COSHH toolkit is designed to make workers aware of the hazardous substances associated to their work, and provide advice on what to do to help prevent ill-health and minimise the risk of accidents at work.

In light of the clear evidence of the danger of serious injury associated with poorly-maintained propane forklift trucks and inadequately ventilated premises where such vehicles are used, we urge employers to make themselves aware of the risks – and ensure their workers are aware, too.


A case study

I was employed in a small warehouse with duties that included driving a gas-powered forklift truck.

When my forklift truck started leaking oil, it was temporarily replaced. Before Christmas, the original forklift truck was returned. It still had a small oil leak.

The maintenance company visited and, while looking at the forklift truck, said that the regulator where the gas goes through kept freezing. They told us to pour warm water over it.

Just before starting my Christmas leave, I was getting an almost constant headache and feeling sick and dizzy. I thought this was due to me wrapping pallets, as you have to go round and round.  During the Christmas break, with 11 days off, the headaches improved and I felt better in myself.

On 2 January, a piece of cardboard had been placed underneath the forklift truck to catch the oil. There was a reasonably big puddle. I remember the manager calling the forklift truck people again, but they didn’t come out.

In the afternoon I remember my boss saying he felt sick and dizzy. At about 3.45pm I also started to feel dizzy and light headed and was sweating. I remember my boss going to the toilet and being sick, and then I went to the toilet and sat on the floor for 10 minutes. I lost consciousness and fell onto the floor. Senior management found me and rang 999. The first response paramedic’s carbon monoxide alarm went off. The fire brigade then turned up wearing breathing apparatus. I was taken to the local hospital and told I had 33 per cent carbon monoxide in my blood. Not only did I lose consciousness but I also hurt my left shoulder when I fell. I was told that I had damaged ligaments.



[1] Rimmer TW, Yarnell SH. Controlling forklifts' exhaust emissions. Occup Health Saf.

2009 Jan;78(1):41–3.

[2] Centers for Disease Control and Prevention (CDC). Carbon monoxide poisoning

associated with use of LPG-powered (propane) forklifts in industrial settings--Iowa,

  1. MMWR Morb Mortal Wkly Rep. 1999 Dec 17;48(49):1121–4.

[3] Pages B, Planton M, Buys S, Lemesle B, Birmes P, Barbeau EJ, et al.

Neuropsychological outcome after carbon monoxide exposure following a storm: a

case-control study. BMC Neurol. 2nd ed. BioMed Central; 2014 Jul 21;14(1):122.