A massive blaze at a Hastings cool store and pack house is now under control, but another fire has broken out at another pack house nearby.

The Turners and Growers cool store in Williams St has been extensively damaged, with fire fighters taking 30 minutes to bring the fire under control.

A fire spokesperson says they are now attending another pack house fire, just down the road.

Witnesses to the first blaze say there was a loud explosion just before 9am. It is believed electricians and other staff members were working in the coolstore when the explosion occurred.

Police say nearly all staff managed to get out unharmed, with one person suffering smoke inhalation.

Williams St has been cordoned off due to the fears about the chemicals in the first cool store. The Hastings District Council is advising all residents living near the site of the huge fire to stay inside and close all doors and windows.