A squirrel caused responsible for leaving more than 40,000 East Bay Pacific Gas & electric customers without electricity on Monday night.

PG&E spokesman J. D. Guidi told the Contra Costa Times that there was no power supply in the areas located in the east of San Francisco, including Berkeley and Oakland, on Monday night after a squirrel 'impacted equipment' at the El Cerrito substation.

The agency also said that the downtown Berkley station of the bay Area Rapid Transit system was also closed for several hours on Monday due to power outage.

Guidi said cities towards the south, including San Jose, also suffered outages on Monday night caused by equipment failures due to triple-digit temperatures.

Guidi said, "The outage was caused by a squirrel that impacted equipment at out El Cerrito substation. We do have crews on-site and multiple personnel working as safely and quickly as possible to restore power this evening".

According to a BART news release, the Downtown Berkeley BART station reopened at 10:10 p. m. after the power outage closed the station around 8:15 p. m.

The utility told KPIX 5 that a squirrel got into the El Cerrito substation and damaged equipment around 8:00 p. m. Monday night.

People who had to deal with power outage even posted pictures on social media of being stuck in the dark, but all were rescued later.

Some even blamed hot weather for outages that impacted about 7,500 customers in the South Bay, particularly around San Jose and Gilroy.