Thousands of firefighters in California continued to make gains today on the massive fire close to Los Angeles, but with temperatures set to soar commanders were still on alert for flare-ups, according to dpa. As of Thursday morning the fire was 38 per cent contain and had burned some 58,000 hectares with full containment expected on September 15. Though the fire still is classified as a threat to some 12,000 homes, it was moving in the direction of remote wildland areas Thursday and many homeowners returned to find their houses undamaged except for a layer of soot. "We were very fortunate, said Lillian Guarino, 89, who lives with her daughter in La Canada Flintridge, one of the most threatened of the foothill communities. "This is the second fire we have had to go through and hopefully the last." Fire officials also said they had won the battle to save the historic Mt Wilson Observatory, a century old technology compound that now also houses many of the television and cellphone towers that serve the Los Angeles region. "We're pretty confident," Los Angeles County Fire Inspector Edward Osorio told the Los Angeles Times. "Mt Wilson is going to be OK." Fire investigators continued to probe the cause of the fire in a cordoned off area close to the Angeles Crest Highway, a two-lane road that runs through the middle of the fire's terrain. On Wednesday they concluded that the fire was human caused, but remained unsure whether it was the result of arson, or an accidental ignition from a cigarette, a campfire or a spark from machinery. The fire is believed to be the biggest in Los Angeles County in over 100 years and has destroyed at least 62 homes. Two firefighters have been killed and 14 injured.