EDWARDSVILLE, Ill. — Even as workers continued to clean up an Amazon warehouse torn in two by a tornado days earlier, attention began to shift Monday to the construction of the facility that collapsed, killing six.
The U.S. Occupational Safety and Health Administration said it had opened an investigation into the deaths. Illinois officials, including local leaders, said they had begun to inquire about the condition of the warehouse before it collapsed. And some worried that construction methods for such facilities were no longer appropriate for a climate expected to see more frequent tornadoes.
"Already there has been an effort to determine some of the challenges, if there were any structural issues, what exactly the storm's trajectory was coming in and affecting the various pieces of the building," Gov. J.B. Pritzker said at a press conference on Monday in neighboring Pontoon Beach.
The Seattle-based e-commerce giant has 5 million square feet of warehouse space across about a dozen facilities in the St. Louis metro area. And nearly all are constructed like the building that collapsed after the tornado bulldozed through the Edwardsville structure, killing six workers, injuring dozens and ripping off roofs, leveling barns and crushing cars along its almost 4-mile path.
The warehouse was built by what's known in the industry as "tilt-up" construction, where steel-reinforced concrete walls are poured flat and raised into position. But such walls, if not connected strongly to the roofs, can fall in, dropping tens of thousands of pounds on occupants inside, said Grace Yan, a structural engineering professor at Missouri University of Science & Technology, at Rolla. And while they can be strengthened to better withstand tornadoes, it's not required in building codes.
"Tilt-up buildings were not invented for resisting tornadoes," Yan said.
Yan said the 2011 tornado that hit Joplin, in southwest Missouri, killed seven in a Home Depot when the 100,000-pound panel walls collapsed.
Amazon leases the warehouse at 3077 Gateway Commerce Center Drive South, developed in 2018 by Creve Coeur-based TriStar Properties and built by Contegra Construction Co. of Edwardsville. It was expanded to 1.1 million square feet in July 2020. San Diego-based Realty Income Corp. has owned it since late 2020, when it paid $41.5 million for it, according to Madison County records.
Realty Income did not respond to a request for comment. A spokesperson for TriStar referred questions to Contegra, which referred questions to Amazon. Contegra founder and managing member Eric Gowin said in a statement that the company was "deeply saddened" by Friday's events.
The building is a "delivery station," where workers prepare orders for delivery by third-party contractors and Amazon Flex drivers, Amazon said. In total, the facility employed about 190 people in multiple shifts.
John Felton, senior vice president of global delivery services for Amazon, said at the Monday news conference that 46 people were at the building on Friday night; 39 at the "take-shelter location" on the building's north side, which was nearly undamaged. But seven, he said, including the six who died, were on the south side where the walls had fallen in.
Amazon spokeswoman Kelly Nantel said the shelter location was an interior part of the building with no windows. She said it was not a "safe room."
The warehouse is a tilt-up concrete structure with a white membrane roof covered by a material called TPO, or thermoplastic polyolefin. Company warehouses across the region — Amazon leases space in St. Peters, Fenton, Berkeley, Sauget, Pontoon Beach and Edwardsville, to name a few — are often constructed the same.
Nantel said that the warehouse was built according to code.
But Pritzker suggested that existing building codes might not be enough to combat the risks posed by ever-more-dangerous storms, and said an investigation will look into updating the rules, given "the climate change we're seeing all around us."
The National Weather Service said Friday's tornado struck at 8:28 p.m., touching down as an EF0 tornado just northwest of the intersection of I-255 and I-270. It then picked up strength, traveling less than a mile before ballooning into an EF3 tornado, the third-strongest on the Enhanced Fujita Scale, with winds 136-165 mph.
The company said the tornado appeared to form in the warehouse's parking lot.
Impact triggered the collapse of a 40-foot-high wall about the length of a football field, which brought a portion of the roof down as well, Edwardsville fire Chief James Whiteford said Saturday.
An OSHA representative said the agency has six months to finish its investigation and issue citations or propose monetary penalties if it finds violations of workplace safety or health regulations.
Yan said she hopes the industry learns from this.
"It is time for us to find ways to improve the performance of this type of building under tornadoes, to save people's lives," she said in an email to the Post-Dispatch. "The integrity of the structural system is essential here."
Amazon announced Saturday night that it would donate $1 million to the Edwardsville Community Foundation to help in relief efforts.
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(Jacob Barker and Austin Huguelet of the Post-Dispatch contributed to this report.)