Crews worked through the day and into the evening battling a two-alarm fire involving storage areas for metals and compressed gases in an industrial area near 19th Avenue and McDowell -- not far from the Interstate 10 and 17 interchange.
After three hours, firefighters said they had control over the fire, but authorities said the incident was still very volatile and dangerous -- the fire consists of compressed gases and flammable metals. Because of those materials, crews declared it a hazmat situation.
FOX 10 chief photographer Jon Noetzel reported hearing multiple explosions coming from the site. They can be seen on video as SkyFOX flew overhead.
Large, billowing black smoke could be seen coming from the structure far across the valley.
The Phoenix Fire Department stated, "We still have a strong boundary set up between the incident and other structures to prevent property loss. At this time Phoenix fire crews are able to enter the hot zone. They are assessing damage to structures, extinguishing large hot spots and monitoring for hazardous substances."
PFD says the fire was caused when a spark from a welder ignited a pile of metal shavings, which are extremely flammable -- a welder was building a gate at the time. The person injured was an adult male, who tried to put out the fire once it started. He suffered mild burns and smoke inhalation.
A fire spokesman says the blaze consumed three structures in about 20 minutes.
No other injuries to civilians or firefighters were immediately reported.
PFD dispatched more than 50 engines and other units to the blaze.
Phoenix police Sgt. Trent Crump said people in surrounding businesses were being asked to evacuate.
Traffic was restricted during the fire, but all lanes are now open.
The Associated Press contributed to this report.