The sulphurous blaze at the Ravensdown fertiliser factory in Napier has been contained.
Ravensdown released a statement this evening saying the fire was under control, although fire crews remain on site.
The Fire Service hopes to open the site within the next two hours.
"Most importantly our staff are safe and well and have all been sent home excluding essential personnel," the statement said.
SH2 has just been re-opened near Napier.
Shift manager at central fire communications Mike Wanoa said the worry now is the massive clean-up ahead.