Three workers suffered serious injuries before the blaze was put out by civil defence teams and police from Sharjah and nearby Dubai and Ajman, all members of the seven-strong United Arab Emirates (UAE) federation, the official Emirati news agency WAM reported.
Troops from the UAE armed forces also helped extinguish the blaze, which broke out at dawn in an industrial zone of Sharjah, WAM said.
The fire ravaged "two warehouses containing inflammable chemical products and a wood depot", the news agency said.
It did not give the cause of the fire, but quoted the operations chief of Sharjah police, Abdullah Mubarak al-Dukhan, as urging owners of commercial and industrial establishments to adhere to safety regulations and take necessary precautions.
The Sharjah fire follows a blaze
in a Dubai mall two days earlier
The nationalities of the wounded workers were not given.
Hundreds of thousands of Asians work in the UAE, many of whom receive low wages and live in difficult conditions.
The Sharjah fire, which took one and a half hours to put out, comes two days after another blaze destroyed a shopping mall in the adjacent emirate of Dubai.
Two civil defence members were treated for smoke inhalation, but no other injuries were reported as the establishment was empty when the blaze broke out overnight on Friday.
The English-language daily Gulf News reported on Sunday that Dubai police had charged 12 Indian workers with negligence for causing the fire that gutted the Oasis Centre.
The workers were conducting renovation work when the fire broke out, it said.
The paper quoted a civil defence official as saying the shopping mall's fire alarm system which should have been connected to the fire station's operations room had been disconnected while the maintenance work was being carried out.