Water Resources Authority has ordered Kenya Pipeline Company to immediately clean up an area at the source of Kiboko River in Makueni County following a leak on the new Mombasa-Nairobi oil pipeline.
KPC technicians already repaired the leak which was detected two weeks ago but did not clean-up the polluted part, raising fears of environmental damage.
Oil spills can have long-term effects on species and their habitats but the severity of damage depends on amount spilled, type and weight of oil.
Local water users and environmentalists fear the spill may contaminate the river given there is no information on duration of the oil leak.
The leak occurred in a forested area at the source of the seasonal river, which locals and livestock depend on periodically.
If KPC does not clean-up the oil spill, Mr Wilson Munguti, who is the chairman of Kiboko Water Resources Users Association, has threatened to lead demonstrations against the firm.
"You are required to clean up the oil spill area within the Kiboko springs water catchment and remove the soil containing the oil product to safer grounds as chances are that they may contaminate the nearby water sources and the indigenous vegetation within the catchment rains," reads a copy of the order seen by the Nation on Wednesday.
The order was issued to KPC on April 8, by Mr John Njuguna, the local Water Resources Authority official.