At least 51 people died and several others remained hospitalized Tuesday after an abandoned tractor-trailer was found in San Antonio amid sweltering heat, in what officials are calling likely the nation’s deadliest smuggling incident on record. 

Bexar County Precinct 1 Commissioner Rebeca Clay-Flores said the death toll rose to 51 people during a news conference Tuesday afternoon. Initially, 46 people were found dead in the trailer Monday and 16 people were hospitalized, authorities said.

Rubén Minutti Zanatta, Consul General of Mexico in San Antonio, said Tuesday that three of the hospitalized patients had died, leaving 13 still hospitalized, including a 16-year-old.

At least two of those 13 were in critical or grave condition, he said. San Antonio Mayor Ron Nirenberg said the victims had “families who were likely trying to find a better life.”

“This is nothing short of a horrific human tragedy,” Nirenberg said. “This is a horror that surpasses anything we’ve experienced before.” 

Here’s what we know at the moment:

Likely the deadliest smuggling incident in US history

The death count was the highest ever from a smuggling incident in the United States, according to Craig Larrabee, acting special agent in charge of Homeland Security Investigations in San Antonio.

The trek migrants face to cross the southern U.S. border is inherently dangerous and hundreds of deaths reported each year. Smuggling is one of several ways migrants make their way into the U.S.

The International Organization for Migration, which is part of the United Nations, said 651 people died attempting to cross the U.S.- Mexico border in 2021 — the largest number since 2014. 

Authorities encountered 239,416 migrants at the southwest border in May — 180,597 more than the same time last year, according to U.S. Customs and Border Protection.

The incident in San Antonio is one of several smuggling incidents along the southern U.S. border that has resulted in death over the years: 

  • July 23, 2017: Eight immigrants were found dead in a sweltering trailer at a San Antonio Walmart parking lot. Two others later died in hospitals. The driver was sentenced to life in prison.
  • May 14, 2003: 19 migrants died inside an abandoned, unrefrigerated dairy truck while they traveled from South Texas to Houston. The truck driver was eventually sentenced to 34 years in federal prison.
  • March 3, 2021: 13 suspected migrants were killed when an SUV crashed into a tractor-trailer in California.
  • Aug. 4, 2021: 10 people died and 20 others were injured after a van carrying 29 suspected migrants crashed in southern Texas.