LOS ANGELES , California ( CNN ) -- The investigation into the massive Station fire north of Los Angeles is underway with authorities working to determine how the raging fire started , fire officials in California said Wednesday . A massive wildfire burns Tuesday near a house in La Crescenta , California , near Los Angeles . Despite reports that U.S. Forest Service spokesman Carlton Joseph said the fire burning in the Angeles National Forest was `` human-caused '' -- either accidentally or intentionally -- other officials insisted that the cause of the fire is under investigation , and natural sources have not been ruled out . `` That information is not validated -- that 's why we 're investigating , '' Angeles National Forest supervisor Jody Noiren told reporters Wednesday , referring to the human-caused report . Thousands of anxious Southern California residents have been displaced by the Station fire burned 140,150 acres by Wednesday . However , Fire Chief Mike Dietrich with the U.S. Forest Service characterized Wednesday as a `` good day , '' noting the fire is 28 percent contained -- up from 22 percent the day before . `` We 're fighting for every foot of containment we can get on this fire , '' Dietrich said . Watch as firefighters are forced on the defensive » . He said firefighters have made progress controlling the northern and western parameters of the fire , but the top priority is to keep the southeastern corner of the fire away from areas along Interstate 210 , including Pasadena , Aracadia and Sierra Madre . The blaze is headed toward the San Gabriel Wilderness Area of the Angeles forest . The San Gabriel represents the eastern edge of the fire , he said . Nearly all of the fire was in forest land and the nearby foothill communities , including La Canada-Flintridge , La Crescenta and Acton . `` This is a very complicated situation , and it continues to be complicated as it moves east , '' Dietrich said . Residents have fled from 10,000 homes along the edges of the Angeles Forest since the fire started last Wednesday . However , the majority of evacuees were allowed back in their homes by Wednesday . Noiren said two dozen Forest Service workers also were displaced by the fire , and the agency lost an entire fire station to the blaze . See images of the wildfire » . Beth Halaas sifted through the ashes of her family 's charred home in Los Angeles County , trying to find something to salvage . `` It 's stuff . Hold on to some of it for traditions . But you 've got to remember it 's just stuff , '' she said on CNN 's `` Campbell Brown . '' See where the fire is burning » . Noel and Marta Rincon had to evacuate their home in Tujunga , on the western side of the fire . Fire was actively burning in the Little Tujunga canyon area , according to fire officials . `` I thought that we were losing our home , '' the husband said of the residence where he was born and the couple raised their family . When a Sky Crane helicopter doused the flames before they could reach the structure , the two were visibly relieved . `` It 's very scary , '' the wife said , `` but our captain over here keeps assuring us our house is very savable and that we are going to be fine . '' See how these wildfires grow » . The fire has destroyed 64 homes , three commercial properties and 49 outdoor structures since it began on August 26 , authorities said . The state has spent about $ 27 million so far fighting the fire in the Angeles National Forest , Dietrich said . Earlier , Gov . Arnold Schwarzenegger was asked about the cost of the firefighting , given the state 's precarious financial position . Watch as governor urges residents to heed evacuation orders » . `` I 've made it clear that even though we have a budget crunch and we have an economic crisis and we just solved a $ 23 billion deficit , we will always have the money available to fight the fires because public safety is our No . 1 priority , '' Schwarzenegger responded . That budget gap covers two years . Watch homeowner : `` It 's completely bombed out '' » . The governor said he insisted that the state budget he signed in July have a $ 500 million reserve for emergencies such as fires . California has had 5,000 blazes so far this year , he said . He said 21 firefighters have been injured battling the Station Fire , in addition to the two killed Sunday in a vehicular crash trying to escape fast-moving flames . Wednesday 's valley and desert temperatures could reach 103 degrees , the National Weather Service said , while mountain highs were forecast to be 100 . While potentially beneficial higher humidity was expected , thunderstorms were possible , and they could bring the danger of dry lightning that could ignite more fires , forecasters said . They also pose the danger of downdrafts that could create more fire fronts , officials said . Cooler temperatures are predicted for the weekend . Schwarzenegger declared a state of emergency Friday as a result of the Station fire . He also proclaimed a state of emergency in several other counties where fires were burning . CNN 's Sonya Hamasaki , Rob Marciano , Chad Myers , John Torigoe and Stephanie Chen contributed to this report .
NEW : Debate over whether it was human-caused -- intentional or unintentional . Deadly wildfire has charred over 140,000 acres in Southern California . Two firefighters killed ; fire 28 percent contained ; up from 22 percent Tuesday . Residents fled from 10,000 homes since fire started last Wednesday .