Pink fire retardant has stained houses and buildings in Los Angeles as the authorities continue to try and slow down the blazes that have killed at least 16 people.

The spray, known as Phos-Chek, has been dropped from nine large planes and 20 water-dropping helicopters across the city to fight the fires that have been burning since Tuesday.

It is made using a mix of chemicals that are used to extinguish or slow down the spread of the blaze, including ammonium polyphosphate – which does not evaporate easily and stays set on materials for longer than water.

The retardant is usually sprayed ahead of the fire in a bid to coat vegetation and prevent oxygen from allowing it to burn.

The bright pink colour is usually added to Phos Chek to ensure that firefighters can see it against the landscape and it is currently covering all the plants, buildings and houses in the areas that have been affected by the flames.

Thousands have been displaced because of the infernos, which have already destroyed more than 12,000 structures while burning through an area larger than the city of San Francisco.

Sewer, water and power infrastructure across the region has been significantly damaged, officials said.

While a cause for the fires has yet to be determined, early estimates indicate they could be the nation’s costliest ever, as experts at AccuWeather put the damage and economic losses at between $135 billion and $150 billion.

The spray, known as Phos-Chek, has been dropped from nine large planes and 20 water-dropping helicopters across Los Angeles to fight the fires that have been burning since Tuesday

The bright pink colour is usually added to Phos Chek to ensure that firefighters can see it against the landscape and it is currently covering all the plants, buildings and houses in the areas that have been affected by the flames

Thousands have been displaced because of the infernos, which have already destroyed more than 12,000 structures while burning through an area larger than the city of San Francisco

Cal Fire reported the Palisades, Eaton, Kenneth and Hurst fires had consumed about 62 square miles (160 square kilometers).

Five deaths were attributed to the Palisades Fire along the coast and 11 deaths resulted from the Eaton Fire further inland, the LA County medical examiner’s office said.

At least 16 people were missing, and authorities said that number was expected to rise.

The flames have threatened and burned through several highly populated neighborhoods over the past week, including Pacific Palisades, Altadena and others.

About 150,000 people were under evacuation orders with more than 700 taking refuge in nine shelters, officials said.

Cal Fire reported containment of the Palisades Fire at 11 per cent and the Eaton Fire at 27 per cent on Sunday.

The Kenneth Fire, which broke out near West Hills in the San Fernando Valley, was 100 per cent contained as of Sunday morning, while the Hurst Fire was 89% contained.

The retardant is usually sprayed ahead of the fire in a bid to coat vegetation and prevent oxygen from allowing it to burn

It is made using a mix of chemicals that are used to extinguish or slow down the spread of the blaze, including ammonium polyphosphate – which does not evaporate easily and stays set on materials for longer than water

A helicopter drops water on the Palisades fire in Mandeville Canyon on Saturday

Los Angeles County firefighters try unsuccessfully to get water from a hydrant as they battle the Eaton Fire

Firefighters fight a blaze as a building burns during the Eaton fire in the Altadena area of Los Angeles county, California

An aerial view of incinerated homes on Pacific Coast Highway on Thursday

Nearly 70,000 customers were without power across California as of Sunday morning, more than half of them in Los Angeles County, according to PowerOutage.us, which tracks outages nationwide.

The National Weather Service warned that strong Santa Ana winds could soon return and issued red flag warnings for severe fire conditions through Wednesday.

The winds have been largely blamed for turning the wildfires into infernos that leveled entire neighborhoods around the city where there has been no significant rainfall in over eight months.

Thousands have fled and many have lost their homes, including Hollywood stars Billy Crystal and Mandy Moore and Los Angeles Lakers head coach JJ Redick.