Residents took to the streets to protest against the construction of a gold dust processing firm in their area.
Led by county assembly members and Ondoa Panya lobby group, the residents of Rostaman area claimed chemicals from the firm could be harmful to their health.
Gold dust has been known to cause mild respiratory conditions.
They complained that they were not consulted before the firm was set up next to a stream that serves as a source of their livelihood.
The residents raised concern over a deal entered into by the county and a Tanzanian investor to excavate gold-laden soil from a disputed 16-acre piece of land.
The land, they said, has been at the centre of a dispute for decades.
They claim to have acquired the piece of land in 1985 and split it into 120 plots, which they shared among them.
They also set aside three plots for the construction of a school, a dispensary and a shopping centre.
"These three plots are the cause of our concern because the county government has allocated a developer rights to take away soil, breaching our rights," said Meshark Ida, a retired teacher.
After an injunction had been issued barring him from extracting soil from the disputed land, the developer last week managed to get a court order allowing him to proceed with the exercise.
MCAs Cleophas Malala, Alex Khamasi and Robert Bushuru said they would petition the assembly to sermon all county government agencies concerned with the lease of the land for questioning.
"We have information that the developer may have flouted many guidelines in setting up the processor and that is why we need the environment executive and other line officials in the assembly for questioning," said Malala.
Khamasi questioned the logic of selling gold-laden soil at Sh300,000.
However, the county environment office termed the protest unjustified and politically motivated, saying there was a public participation forum before the firm was set up.
