As a result around 80 people have been evacuated from their homes on Wood End Lane and have been temporarily re-housed for safety reasons.
Police cordons are also in place at a 200 metre radius as part of the ongoing policing operation, and negotiators are at the scene.
A number of roads have been closed in the area on Whitton Avenue West between Wood End Lane and Pett's Hill.
The Metropolitan Police said officers have been in attendance since just before 1am in the very early hours of Saturday (October 22) morning.
Officers have said they are treating seriously reports that the items could be dangerous and the man has made attempts to prevent access to the address.
It is not known what the man has inside property.
The Metropolitan Police have said the incident is not terrorist-related.
For safety reasons people living in the immediate area have been temporarily re-housed, while police deal with the incident.
Police would like to thank the local residents directly affected by the incident for their cooperation and patience in the matter.
Officers in Ealing are on duty around the area to talk to the local community and address any concerns people may have.
Police are working with the London Ambulance Service, London Fire Brigade and Ealing council.
Police priority is to ensure the incident is brought to a safe end.