Mysterious noise rattles San Luis R.C.

The city of San Luis Rio Colorado, Son., was rattled Thursday morning by what residents said sounded and felt like an explosion.

Shortly after 10:30 a.m., residents heard a loud rumbling noise accompanied by vibrations that caused windows of businesses and homes around the city to shake, the city's civil protection director, Juan Ramirez Munoz, told the news blog site elinformantesanluis.

Ramirez said he did not know the cause of the incident, and police in San Luis Rio Colorado, Son., told Bajo El Sol Thursday afternoon they had received reports of an explosion but had not confirmed them. Bajo El Sol could not reach Ramirez for comment.

The noise and shaking was followed a half-hour later by an ammonia leak at Bustamante, Parra y Asociados, an onion packing shed on the outskirts of San Luis Rio Colorado, but authorities said they couldn't confirm if the reports of an explosion and the leak were related.

The news website sanluisrc.com quoted police as saying six employees of the packing shed were injured, while elinformantesanluis reported 10 workers were affected.

Area residents inquired about the source of the noise and shaking in postings on the Facebook pages of both Bajo El Sol and the Yuma Sun.

Neither the Somerton/Cocopah Fire Department nor the fire department in San Luis, Ariz., was asked to send firefighters across the border to provide an emergency aid, spokesmen for those agencies said. Luis Cebreros, a firefighter and public information officer for the San Luis Fire Department, said he was aware of a loud noise and shaking.

“I heard a loud bang, and I felt a rumble. I went outside and my neighbors heard it also.”