Police in Kisumu guarded a tanker that overturned at the Kasagam flyover to prevent locals from siphoning fuel.
The tanker overturned around 7.30 pm, police said.
The incident happened just a day after a fuel tanker exploded and 14 people who were siphoning fuel from it were killed in Gem. At least 29 other people were hospitalised with serious burn injuries.
The fuel tanker overturned as the driver was trying to negotiate a sharp bend to join the Kisumu-Nairobi highway, police said.
A team of police officers from Kisumu led by county commander Samuel Anampiu arrived at the scene and cordoned off the area.
Police said the driver of the tanker escaped after the incident.
"The truck driver has not been found and efforts to trace him is in progress. The truck is still at the scene," said Mr Anampiu.
Firefighters arrived at the scene to contain spillage.
Also present at the scene were personnel from the Kenya Red Cross, National Transport and Safety Authority and the Energy and Petroleum Regulatory Authority.
By Tuesday morning, the fuel was still spilling into a stream that pours its water into Lake Victoria.
There are concerns of pollution of the lake.
"We are sad that the marine life is threatened and we will have to work with National Environment Management Authority to assess the level of contamination and mitigation measures we can apply to ensure the spillage doesn't cause any more harm," said Mr Anampiu.