The two had filled an exhauster truck and were about to leave before tragedy struck.
The turn-boy was the first to slide into the 8-metre deep pit. The driver fell while attempting to rescue his colleague.
Samuel Lumumba said he was called by the driver to assist in the rescue mission but the latter slid before he could reach him.
“I was grazing cows when the driver called me. He fell as he attempted to remove his friend from the pit,” Lumumba said.
It was not immediately established how the first person fell into the pit.
Peter Mwangi, a Nyahururu Water and Sanitation Company official, said the two were workers of an institution licensed to empty sewer manholes.
He said the two must have died from Hydrogen Sulphide poisoning.
“The gas kills within minutes. It could have been impossible to rescue the said persons,” Mwangi said.
He cautioned residents against going near or opening manholes to avert such incidents.
The bodies were retrieved and taken to Nyahururu referral hospital mortuary.