Aircraft battling fires raging through the Los Angeles area are dropping more than water -- hundreds of thousands of gallons of hot-pink fire suppressant ahead of the flames in a desperate effort to stop them before they destroy more neighbourhoods. The fires have killed at least 24 people, displaced thousands and destroyed more than 12,000 structures since they began last Tuesday. Four fires driven by strong Santa Ana winds have charred about 160 square kilometres, according to Cal Fire. Fire agencies say the suppressants -- most often used to fight forest fires -- are an invaluable tool. But what is in them and are they safe? Why they are being used in Los Angeles The fires are burning quickly through canyons and other rugged areas that are difficult for firefighters on the ground to reach, Cal Fire said. While fire suppressants can be very effective, they do have limitations, the agency said, "Strong winds can make it too dangerous to fly at the low altitudes needed for drops a