Biogas in room likely cause of city explosion, say investigators

By Cyrus Ombati

Investigators believe the powerful explosion that rocked Kirinyaga Road on Sunday was caused by biogas from an underground room of a petrol station.

Preliminary tests showed a high concentration of hydrogen gas in the room, which could have been part of the cause of the blast.

A team handling the case said on Tuesday the concentration was above 50 per cent, suggesting there was a form of production of biogas in the room.

In the basement room that had been tightly closed, there were traces of sewage, oil, dirty water and other biomass materials. This according to the experts could have formed biogas that led to the blast.

But the officers were awaiting further tests to confirm the suspicion. Officials from the Fire Department used a special device to measure the concentration of the hydrogen.

They, together with bomb experts, Kenya Power and Lighting Company, and those from Shell visited the scene again on Tuesday. Shell has hired an expert also to investigate the blast.

"Hydrogen is highly flammable and will burn in the air at a very wide range of concentrations between four and 75 per cent by volume. This could be the cause but let us wait for the final report from the Government Chemist," said one official at the blast scene.

The sewage waste in the room, from where the blast originated, has hampered further work at the scene.

The petrol station management says the room had been closed for close to a decade.

Police were also pursuing a theory that after the production of the gas reached its climax, a smoker or fire from outside the room may have triggered it.

Director of CID Ndegwa Muhoro said preliminary analysis have ruled out a bomb explosion. He also ruled out an electrical fault as the possible cause of the explosion.

"They say there was a high concentration of hydrogen there but let us wait for the final results. But it was not a bomb," said Muhoro.

He added that the investigators had combed the blast site but did not find any of a bomb.

Two men were killed in the explosion and 25 of 42 who were injured were still admitted to Kenyatta National Hospital on Tuesday.

The area of the explosion is a busy street behind Kirinyaga Road that is usually frequented by motor vehicle mechanics, dealing in second-hand spare parts.

Other experts who arrived at the scene suspect the explosion was caused by a fuel leakage from the underground tanks that are at the same level of the room where the explosion occurred.

Most of the victims were hit by flying objects that were triggered by the explosion that occurred at about 11.30 am on Sunday. Others in hospital had serious burns on their bodies.

Some experts who arrived at the scene had suspected the explosion to have been caused by a fuel leakage from the underground tanks that are at the same level of the room where the explosion started.