MEXICO CITY — A fire broke out at a recycling plant on the outskirts of Ciudad Juarez on Wednesday, sending thick clouds of heavy black smoke billowing across the border city and into neighboring El Paso, Texas.

The Juarez municipal government said via Twitter that the fire was reported at 2:30 a.m. on a 911 call. By early evening, it reported that the blaze had been brought under control with a perimeter established, but said firefighters were still trying to extinguish it.

Mayor Armando Cabada said via Facebook that there were no injuries, but he added the blaze was creating "environmental damage" with winds carrying the smoke northward.

Juarez authorities declared an environmental emergency due to harmful particulate matter in the smoke, and people in its path were advised to stay inside, shut windows and doors and not use air conditioners.

Firefighters sprayed water on burning piles, but Juarez civil defense chief Efren Matamoros described as highly flammable, compacted bales of plastic, cardboard and other material.

"When these bales catch fire, it is impossible to extinguish them until they consume themselves," Cabada said.

He added that authorities were investigating whether the recycler has been operating with the proper permits.

"We are tracking down the owner of the lot, the owner of that recycling plant, to press charges because it is causing severe damage to our environment," Cabada said. "Regrettably, the wind today has a south-to-north direction, and it's contaminating practically the whole city."