Nearly one month after a fire destroyed a massive cold-storage facility in Boyle Heights, the neighborhood has been overcome by the stomach-churning stench of rotting food.

As facility operator Lineage works to remove more than 85 million tons of weeks-old food from its 500,000-square-feet warehouse, the rancid odors have attracted throngs of rats and swarms of flies, as a foul-smelling brownish liquid pours from the seams of the building.

Now, with a heat wave descending over much of Southern California, residents worry the odor could get even worse and scores of residents have called air quality regulators to complain. At the same time, environmental groups are accusing Lineage representatives and emergency responders of downplaying the risks pose by chemicals released during the fire.

Boyle Heights, a neighborhood that has been subjected to decades of toxic pollution from rail yards and other industries, has again become the center of attention in another environmental disaster. Already, the official response to the Lineage fire has eroded trust in government agencies, residents say.

On Tuesday, Sen. Alex Padilla (D-Calif.) visited the gutted warehouse alongside L.A. Fire Chief Jaime Moore and representatives of the South Coast Air Quality Management District and a contingent of environmental organizations. Padilla, along with Sen. Adam Schiff (D-Calif.) and Rep. Jimmy Gomez (D-Los Angeles), wrote a letter to the U.S. Environmental Protection Agency, calling on the agency to return to the cleanup zone to monitor air and water quality.

“Given the materials present in the warehouse, we are concerned about the long-term health and environmental impacts from contaminated smoke and water runoff on communities surrounding the warehouse,” the letter read.

Joe Lyou, president of nonprofit Coalition for Clean Air, told Padilla that he has heard of people becoming sick in the weeks after the event.

“I think that pointed to a problem with the messaging while the event first happened,” Lyou said. “It wasn’t consistent [with] if you smell smoke, see ash to get out and protect yourself — make sure you’re not exposed to it. There were different messages coming from different people, and we need to fix that.”

“The whole community was completely overwhelmed … and concerned about the ammonia, concerned about burning plastic, concerned about all sorts of other [emissions] that are really hard, difficult, expensive to measure. But … we’ll just never know some of those things,” Lyou said.

Street vendor Lupe Gonzalez pushes her cart away from a gutted warehouse in Boyle Heights.

(Allen J. Schaben / Los Angeles Times)

Chief Moore has faced criticism for his decision to advise residents to shelter indoors rather than to evacuate during the blaze. That stood in sharp contrast with Orange County fire officials, who evacuated tens of thousands of residents near an overheating chemical tank in Garden Grove in May.

On Tuesday, Moore told Padilla that the two incidents were very different. Moore said he had discussed the dilemma with TJ McGovern, the interim fire chief for the Orange County Fire Authority.

“He says everybody got mad at him because he evacuated everybody and nothing blew up,” Moore told Padilla. “But everybody’s mad at you because of the shelter-in-place [order] and it smells.”

Moore said that “there was nothing in the air that was hazardous” and that firefighters “never had a threat of an explosion.”

However, environmental experts said 14,000 pounds of flammable anhydrous ammonia were stored in tanks and used as refrigerant at the Lineage warehouse and posed a significant risk of explosion until it was removed days into the fire.

Environmental and community groups said L.A. fire officials also repeatedly emphasized the risks from ammonia in their radio communications. On the first day of the fire, a group of firefighters was hit by a plume of ammonia gas, and fire command quickly organized medical help.

“The majority of my division got exposed to ammonia gas. We’ll need to get them assessed.”

On Tuesday, Moore said no amount of ammonia was detected.

“When [firefighters] opened those doors, there was what looked like a big vapor cloud that came out,” Moore said. “That was the cold air mixing with the hot air that caused a vapor. It wasn’t ammonia.”

But residents remain skeptical.

Padilla’s visit follows a notice of violation that the South Coast Air Quality Management District issued to Lineage. The notice of violation was issued on July 12, after the agency received more than 40 public complaints of rotten, sour, garbage-type odors in the area. Inspectors confirmed the odors with community members and traced them back to cleanup operations at the facility, according to the air quality agency.

Boyle Heights residents are calling on Gov. Gavin Newsom to declare a mandatory evacuation of their community, saying the fire and the toxic aftermath are continuing to pose health risks. Without an evacuation order, they said, insurance companies won’t help residents who want to relocate with rent or mortgage relief.

“For nearly a month, a cold-storage warehouse fire has poisoned the air over the Eastside and Los Angeles County and City officials have refused to issue a mandatory evacuation,” read a statement from the community group Protect LA Now. “That refusal forces victims to pay their own way out, and leaves those who can’t afford to leave trapped in gases and toxins that no agency will name.”

Joe Lyou, president of the Coalition for Clean Air, explains how smell is affecting his health while talking to the media near a fire-gutted Lineage facility Tuesday.

(Allen J. Schaben / Los Angeles Times)

Tensions have been building in the community since the fire broke out on June 17 and burned for days.

At a contentious town meeting last week, Los Angeles Mayor Karen Bass struggled to open the meeting over the loud boos and yelling of community members, actions that were repeated as other elected officials took the microphone. The crowd grew even louder when Lineage Chief Operating Officer Jeff Rivera took to the stage and was met with shouts of “Liar!”

Air quality has been a constant concern for the community since the incident began. Beyond the health hazards of breathing in smoke from a building fire, there was a brief, temporary scare when an ammonia line that helped keep the building refrigerated was compromised, though Lineage has said the chemical was not detected in the air. Additionally, 85 million pounds of food thawed, burned and spoiled inside, creating a terrible smell that emanated from the property.

Nora Saenz, a resident of Bell, said she believed local leaders when they said there was no threat. During the fire, she took her niece and nephew to a community event in La Mirada, which was downwind of the fire.

Now Saenz fears what they might’ve breathed in.

“The day of the fire, we were told that the air was safe to breathe,” she recalled. “To this day, I don’t know what I exposed my niece and my nephew to.”

Times staff writers Salvador Hernandez, Clara Harter and Seamus Bozeman contributed to this report.