SYLMAR (CBSLA) – Hundreds of firefighters continued to make progress Tuesday on the Saddle Ridge Fire which broke out last week and spread across the San Fernando Valley foothill communities of Porter Ranch, Granada Hills and Sylmar.

The point of origin of the Saddle Ridge Fire in Sylmar, Calif., located below a Southern California Edison high-voltage transmission line. Oct. 14, 2019. (CBS2)

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This comes as the Los Angeles Fire Department reported Monday that its arson investigators had narrowed down the point of origin to a 70-by-50 foot area beneath a Southern California Edison high-voltage transmission line off the 14000 block of Saddle Ridge Road in Sylmar.

There is no evidence of a homeless encampment in the area, the fire department disclosed.

A SoCal Edison spokesperson told the San Francisco Chronicle Tuesday that the utility had alerted the California Public Utilities Commission on Oct. 11, the day after the fire started, that it’s “system was impacted near the reported time of the fire.”

However, LAFD said there is still no definitive cause to the blaze. Investigators with both SoCal Edison and private insurance companies are also on site assisting with the investigation.

The Saddle Ridge Fire, which broke out on the night of Oct. 10, was at 8,391 acres and 45 percent contained as of 7 a.m. Tuesday, according to the Los Angeles Fire Department.

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Oct. 14, 2019. (CBS2)

The fire destroyed 17 structures and damaged 77 more. At its height, it forced more than 100,000 people to flee their homes. However, all evacuation orders have been lifted and all schools reopened Tuesday. Schools were providing students and staff with masks to protect them from the smoky air conditions.

Oct. 14, 2019. (CBS2)

About 1,000 firefighters from several agencies are still fighting the fire, mopping up hot spots and setting containment lines. They have been helped by lower wind speeds and increasing humidity, the fire department said.

Meanwhile, Southern California Gas notified LAFD Monday that an active 4-by-4-foot fire had been discovered in the soil of the Aliso Canyon natural gas store facility. There were no signs of a methane leak or that the fire had caused any damage to the facility itself, however.

In 2015, Aliso Canyon was the site of the largest methane gas leak in U.S. history. Beginning in October 2015, the Aliso Canyon underground storage facility spewed about 109,000 metric tons of methane into the air and led to the temporary relocation of about 7,000 Porter Ranch-area residents. The leak was not capped until February 2016.

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One person died of a cardiac arrest as a result of the Saddle Ridge Fire and three firefighters suffered minor injuries.