Source of explosions heard across the San Gabriel Valley remains a mystery

In the middle of the night, Daniel Recinos and his family were fast asleep in their Baldwin Park home when three thunderous explosions violently woke them up. 

"I woke up and I was like, 'What's going on? Are there explosions outside?" said Recinos.

The explosions were heard in multiple cities in the San Gabriel Valley, however, the source of the explosions remains unknown. KCAL News called police and fire departments in Covina, El Monte, Pomona and Azusa as well as city managers, electric and gas companies but none of those agencies know what caused these mysterious blasts that lit up the sky last night. 

"Being that loud it's kinda scary. You have to wonder what it was," said Recinos. "I've heard everything from the Chinese spy balloon to just fireworks."

One prevailing theory from some San Gabriel Valley residents involved the nearby rock quarries. 

"It's normal when you hear a bang outside... It's got to be Vulcan," said Azusa resident Jeri Bibles Vogel. 

Vogel lives near a rock quarry and said she hears similar blasts all the time. She also said she once spearheaded a campaign to put a stop to all the noise. However, a worker with Vulcan told KCAL News that it wasn't the construction company blowing rocks up last night. 

Another worker speculated that it may have been other nearby rock companies may have caused the blasts last night. 

"It isn't nice," said Vogel. "It wakes up small children. Kids are going to school, people are going to work."

Recinos also lives near rock quarries. A worker said that companies schedule blasts in the night for safety reasons.

"It's a little scary not knowing where these things come from and what it could be," said Recinos. Everyone wants answers."