A major fuel pipeline explosion and fire occurred in the Mukuru-Sinai slums of Nairobi, Kenya, leading to more than 100 people dead, and an equal number hospitalized with major burn injuries. The Rapid Environmental Emergency Assessment conducted by the United Nations Office for the Coordination of Humanitarian Affairs (OCHA) and the United Nations Environmental Programme (UNEP) through their Joint UNEP/OCHA Environmental Unit (JEU), determined that the fire was not caused by a pipeline explosion as initially reported, but by an industrial accident that caused a large amount of petrol to enter a nearby storm water drainage system. The location where the fire took place is affected by pre-existing, chronic pollution and therefore no immediate clean-up action is warranted to remove the remaining residues of the accident. It was also determined that there is no immediate threat to the drinking water supply. It was concluded that there is a clear indication of uncontrolled industrial effluents being released into the storm water drainage system and the Ngong River. This report focuses on humanitarian issues in an urban, environmental context. Reflected in the report are the detailed recommendations for immediate measures to be taken, as well as the suggestions to improve the preparedness for environmental emergencies at both the national and local level through the implementation of UNEP's programme on Awareness and Preparedness at the Local Level (APELL).