A security company has been fined £20,000 after a security guard was killed by carbon monoxide fumes from a petrol generator in Gravesend.

Arthur Ebirim, 45, was overcome by the killer gas as he kept a night-time watch over a disused nursing home in Taunton Vale awaiting demolition.

His employer Anchor Services was prosecuted by the Health and Safety Executive (HSE) after an investigation identified serious flaws with how the generator was used.

Dartford Magistrates' Court heard Mr Ebirim and colleagues had been assigned to security at the nursing home since early August 2011. The guards were initially stationed outside the building before moving into a lobby area inside as the weather cooled.

The petrol generator belonged to one of the workers and was also placed inside the lobby to provide a power source.

On the evening of October 27, 2011 Mr Ebirim was asked to guard the home alone because the usual night-time guard was unavailable. His wife raised the alarm that something was wrong when he failed to contact her at the end of his shift the next morning.

"This was a tragic and completely avoidable death that has devastated Mr Ebirim's wife, family and friends. Their loss is made worse by the fact he was only covering the night shift as a one off, but sadly never returned home..." - HSE inspector Melvyn Stancliffe

Company representatives went to the site but were unable to gain access to the office. The door was eventually broken down by the emergency services and Mr Ebirim, from Peckham, south east London, was discovered slumped in a chair.

He was pronounced dead at the scene. A post mortem examination later confirmed carbon monoxide poisoning as the cause of death. An inquest concluded a verdict of accidental death.

The HSE investigation established the only source of carbon monoxide in the room was the petrol generator. Tests revealed it was capable of producing fatal levels.

The generator was placed next to a door leading to a courtyard, and a sign on the door stated: "When running the generator please keep this door open."

But generators of this kind are designed for outdoor use and should never be used indoors.

HSE inspectors also found it was prone to running out of fuel in the early hours of the morning, according to a log book at the site. Refilling in the dark posed an additional safety risk because there was a greater chance of spilling petrol and causing a fire.

The court was told Anchor Services failed to assess the risks posed by the generator and also failed to implement its agreed lone working procedures on the night of Mr Ebirim's death.

The company, formerly of Tanfield Road, Croydon, but now in the hands of Sutton-based liquidators Turpin Baker Armstrong, was found guilty in absence of breaching Health and Safety rules.

It was fined £20,000, the maximum penalty available to magistrates, and was ordered to pay a further £35,656 in costs.

HSE inspector Melvyn Stancliffe said: "This was a tragic and completely avoidable death that has devastated Mr Ebirim's wife, family and friends. Their loss is made worse by the fact he was only covering the night shift as a one off, but sadly never returned home.

"The bottom line here is that the generator should not have been used inside the building, even with the door open.

"Petrol generators must only be used in a well-ventilated area because they are known to emit carbon monoxide.

"The onus was on Anchor Services (GB) Limited to keep Mr EIbirim safe, but they failed to do so."