2 dead in Houston explosion that destroyed building, caused 'significant' damage to homes

The two victims killed in an explosion at a Houston manufacturing facility have been identified, authorities said.

Gerardo Castorena and Frank Flores, both employees at Watson Grinding and Manufacturing, were killed in the early-morning blast at the site on Friday, according to the city's police and fire chief.

The manufacturing company issued a statement expressing its condolences to the families of the victims, but did not name the two employees who were killed.

"Our hearts go out to the families and businesses impacted by this incident and to our community," the statement read. "At this time, our immediate concern is the safety and well-being of everyone in the area and our employees."

The company was "working diligently" with federal, state and local authorities to investigate the accident, according to the statement.

It was not yet clear exactly what caused the explosion, but Houston Fire Chief Samuel Pena noted there was a leak coming from a 2,000-gallon tank of propylene.

Multiple homes and a nearby strip mall also sustained "significant damage" in the blast, which happened around 4:30 a.m. local time on Friday, Pena said at a press conference.

Houston Police Chief Art Acevedo said a full arson investigation had been launched, but noted that there is no reason to believe it was terror-related or an intentional act. He said it is protocol to conduct an investigation and that it will be handled by multiple agencies to ensure that regulations had been followed prior to the explosion.

Authorities urged residents who felt the blast to search around their homes for debris and body parts. Acevedo warned the public not to touch either if they do find them, but to instead call Houston police.

Drones were also brought in to conduct a grid search and inspect roofs for debris.

Around 18 people checked in at local emergency rooms, complaining of minor injuries from the blast, according to the Houston Fire Department.

The propylene leak has been secured and there are no concerns with air quality at this time, Pena said.

As of Friday afternoon, authorities were waiting for a fire that was sparked by the explosion to burn out before conducting additional searches. Although contained, the fire was not being extinguished manually by firefighters in order to avoid creating a runoff or other hazards, Pena said. ATF was also on the scene assisting.

The explosion was so strong that nearby residents between Gessner Road and Steffani Lane in Houston's Westbranch neighborhood reported doors being blown off their hinges, baseboards blown off and storm doors shattered, according to Houston ABC station KTRK. The force of the blast rattled windows for miles around.

Following the explosion, temporary shelters were set up at 4703 Shadowdale Drive. At least 48 people were sheltering there, according to KTRK.

Acevedo asked for the public to consider offering help and donating to the families who had been affected.

"This is an area where it isn't the most affluent, so my thoughts are with all the individuals, whether they rent or own, that will be potentially displaced," Acevedo said.

ABC News' Rebecca Patterson contributed to this report.