BROWNSVILLE – Several residents in a Brownsville neighborhood are concerned about an oil-like substance in their area.

The neighbors told CHANNEL 5 NEWS they’re asking if it is dangerous and want to know how the substance got into the area.

Resident Esther Garza has lived in her neighborhood for nearly 10 years. She said she noticed a black oil like substance near her backyard on Tuesday.

"I saw everything filled with oil yesterday. I wondered what happened or why it happened. People see it but they don't know what's going on," she said. 

Garza wants to know if the substance is hazardous. She said she wants to know if it can be harmful to any of her 12 grandchildren and nine great-grandchildren who visit her home and play nearby.

"What if it affects something or it gets in the water pipes? A lot of things can happen," she said. 

CHANNEL 5 NEWS reached out to Cameron County Deputy Administrator Javier Villarreal. He said it’s a petroleum-based substance called AEP Emulsion that's mixed with water and used to build roads.

Villarreal said it's a non-hazardous material.

"It's an erosion control, and to actually harden the caliche base that's laid down prior to the asphalt being laid on top of it," he said. 

Villarreal said the runoff is due to Tuesday’s rain. He said crews are trying to contain the substance.

"They're called socks or containment barriers. You roll them out and they're just super absorbent tube-like looking product that is for that purpose, to actually absorb any kind of spillage or if you want to contain certain things in a certain area, it keeps it from spreading," he explained. 

Villarreal said residents can be assured crews are handling the situation properly.