() California is the only state to ban the most lethal type of rat poison, so more rodents are living large these days, especially in Los Angeles.

According to pest control experts, the rat population is booming, and service calls are way up.

headed out with rodent expert Louis Rico, and it took just 30 seconds for him to spot a rat burrow in someone’s front yard. 

The rodent residents were not home.

Proponents had pushed for the ban on “anticoagulant rodenticides” to protect pets and wildlife that might feed off toxic dead rats. 

When Gov. Gavin Newsom first signed the law, J.P. Rose, Urban Wildlands policy director at the Center for Biological Diversity, said in a statement that it was a “relief to know the deadliest rat poisons will soon be off the market here.”

“This important legislation shows why California is an environmental leader. We’re willing to fight for wildlife protections,” Rose said in a statement. “Birds, foxes and pumas shouldn’t be sacrificed every time there’s a pest problem.”

However, according to exterminators, other types of extermination techniques just aren’t as effective as anticoagulant rodenticides.

As a result, there has been a ballooning rodent population. Some say this could lead to a potential public health crisis.

Chicago has claimed the top spot as the United States’ rattiest city for 10 years straight, and Los Angeles is at No. 2.

New York City is ranked third in cities with the most rats. San Francisco and Washington, D.C., round out the top five.

The California rodenticide ban could mean a change is underway.

“My prediction is that probably by the end of the year, we will become the rattiest city in the United States, for sure,” Rico, owner of American Rat Control in Los Angeles, said. “I’m wishing, hoping that we can get some of the old rodenticide back. That really worked.”

The Southern California wildfires are another factor in the booming rat population.

Many people were displaced during the deadly blaze, and rodents have been as well, so many have made their way into surrounding communities.

Rat sightings are up in San Francisco as well, prompting a column just yesterday in SFist on whether that city needs a rat czar like the one in New York City.

In a single year, just two rats can produce thousands of offspring. Female rats can start reproducing five weeks after birth, and each can deliver litters of up to 12 every month.

This is why many are pushing for more aggressive efforts in rat birth control, along with higher public awareness to combat habits that attract rats, like leaving out bird seed, pet food and garbage.