FONTANA ( — Firefighters Monday continued to work to extinguish hot spots caused by a massive fire at a 5-acre pallet yard in Fontana.

The three-alarm fire was first reported shortly after 10 p.m. in the 13800 block of Slover Avenue, according to San Bernardino County Fire Department.

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It quickly spread causing flames to reach more than 100 feet high.

“With that much heat and that intense of a fire you can put a lot of water on it before it starts to make any effect,” Batt. Chief Ronald Walls said.

Officials say the fire was contained early Monday morning but some crews will remain on site throughout the day to monitor any flare ups.

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Several passenger-type vehicles as well as an estimated 18 semi-trucks were damaged — including six that were completely destroyed.

“I believe we’re estimating the damage at about $1.5 million,” Walls said. “But we think that there is probably a good $6.5 million in saved property, that includes several businesses that are in close proximity and a number of semi-trucks.”

Two firefighters suffered minor injuries while battling the flames.

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The cause was under investigation.