Kuniyoshi said fire officials are aware of witnesses who said a man threw something into the brush that ignited the blaze, but added that the fire's cause was still undetermined.
Burrell Assistant Chief Craig Davis said one of his department's firefighters was OK, but overexerted himself and had trouble breathing.
It took firefighters from five departments just over three hours to put out the fire, which burned about 7 acres. However, there have been no reports yet of any buildings catching fire.
Meanwhile, the National Weather Service issued a special statement for Friday warning of low humidity, dry conditions and possible wind gusts as high as 35 miles per hour.
Remain groups team up to push for second Brexit vote
Campaigners including actor Sir Patrick Stewart and politicians from across the political spectrum are demanding a second vote. The People's Vote aims to unite anti-Brexit groups, with a rally being held in Camden, north London, on Sunday.
Middlesex fire crews were already on the scene of a mower on fire on Kyle Road when the call came in.
The fire was listed as contained as of 6:15 p.m.
Dispatchers said the Wildland Task Force has been activated to help fight the fire.
Outdoor burning is not recommended.