LA's world-famous Fashion District has become the city’s unofficial garbage can, anchored by a quickly expanding 12-ton mountain of trash that’s the result of months of illegal dumping, creating a massive public health nightmare.

Update (9:21 a.m. Friday): Aerial video shows a striking difference at the site after the I-Team's report. City crews removed the piled up trash overnight.

Frustrated business owners contacted the I-Team to show us how a burned out commercial building on East Pico Boulevard, once a clothing showroom, has become a dumping ground for an estimated 12 tons of trash. That's even after their repeated calls to 3-1-1 to clean up the mess that’s swarming with rats and flies.

The trash from the building is spilling out into the public alley, where it's a breeding ground for armies of rodents. And, homeless people are living in the huge health hazard.

"This is embarrassing," said Joe Song, owner of Glam Apparel, which backs up to the trash mountain. “In the heart of Los Angeles, I cannot believe we have this. And there’s nobody doing anything about it."

Buyers and customers from across the U.S., Asia, and South America flock to LA’s Fashion District every day. But these days, as they drive into the district, they’re greeted by homeless encampments and pile after pile of uncollected waste that’s been illegally dumped.

No pile appears bigger than the one that keeps getting higher at 771 East Pico, the former showroom of Priceless Apparel. The building went up in flames in February 2018. According to LAFD records obtained by the I-Team, the fire’s origin was traced to a homeless encampment.

Since then, businesses surrounding 771 East Pico have called 3-1-1 twenty-three times to get the site cleaned up, but they say the city isn’t taking action.

"And it just gets worse," says Rena Leddy, executive director of the Fashion District Business Improvement District.

“There’s urine, feces, there’s flies all over the place,” Leddy told NBC4 as she walked by the Fashion District garbage heap.

That all changed Thursday afternoon, when the I-Team spoke with Mayor Eric Garcetti by phone. Garcetti is in Honolulu attending the U.S. Conference of Mayors.

Garcetti said he was unaware of the huge health hazard in the Fashion District, but added "I’d like that cleaned up today."

Within an hour of the mayor’s call with NBCLA, city sanitation crews were at the site cleaning away tons of trash.

Thousands of people work and conduct business every day in LA’s Fashion District. Business owners worry about the filth from rodents and uncollected trash driving away customers and clients. But they have an even bigger concern.

“More importantly is the health issue,” said Joe Song, owner of Glam Apparel. "There’s rats carrying disease!"

The I-Team’s cameras documented more than 100 large rats crawling out of the East Pico trash heaps, toward Glam Apparel and other Fashion District businesses over the course of just 45 minutes this week.

LA City officials say illegal dumping of trash has been on the rise. In the wake of an I-Team investigation into a long-neglective garbage pile on Ceres Street, near the produce district, Mayor Eric Garcetti last month announced a new crackdown on those who illegally dump, and said the city has issued dozens of citations.

The I-Team reviewed 25 illegal dumping citations issued by LA this year and found the biggest penalty was $233. That’s less than the cost of some parking tickets in the city.

“A $233 ticket doesn’t really discourage illegal dumping,” said Rena Leddy of the Business Improvement District.

She told the I-Team that businesses that illegally dump are trying to avoid paying the thousands of dollars a month it would cost to legally dispose of their trash.

Business owners have also complained to the LA County Public Health Department (DPH) about the tons of filth piled up at 771 East Pico. Records obtained by the I-Team show DPH issued a “courtesy notice” to the property owners in January to clean up the uncollected trash and rodents.

But the trash pile has apparently only gotten bigger, local businesses say, while the health department and the LA Department of Sanitation have failed to get it permanently cleaned up.

The LA Bureau of Sanitation BOS late Thursday told the I-Team it has done some cleaning in the alley behind the trash-filled building six times this year.

But the I-Team found the alley full of garbage and rats this week. BOS assistant general manager Pepe Garcia told NBCLA his crews today again cleaned up trash from the alley around 771 East Pico. But most of the tons of rotting trash are inside the burned out building, and Garcia says that might not be cleaned up until July 14, because the city has to give homeless people living inside a chance to move.

The I-Team left messages for the property owner, asking for a comment, but has yet to receive a response.