Emergency services are at the scene of a large explosion which occurred on the Slough Trading Estate around 10:00.
The force of the blast was so big that some witnesses nearby thought it was an earthquake.
Berkshire fire and rescue say they are battling a blaze at a plastics and chemical plant.
Crews were called to the Duco International plant which provides printing and varnishing services for metals and plastics.
A spokeswoman for Thames Valley Police said [...] it was thought to have been a chemical explosion but it was unclear if anybody had been injured.
More than 30 firefighters are at the scene tackling the fire.
Slough Trading Estate was Britain's first business park and hosts 500 companies employing around 20,000 people. Its most famous tenant is the fictional paper merchants Wernham Hogg, from the Ricky Gervais sitcom The Office.
Forty firefighters tackled the subsequent fire, Ellie Gray, spokeswoman for the Royal Berkshire Fire and Rescue Service said in a telephone interview. The fire, which started around 10 a.m. today local time in external machinery attached to a manufacturing plant measuring 10 meters (33 feet) by 80 meters, was put out, Gray said at 11.45 a.m.