On the evening of December 10, 2021, the Amazon Logistics DLI4 delivery facility in Edwardsville, Illinois collapsed after being struck by an EF3 tornado, killing 6 workers in the facility and injuring 4. The building was constructed with a storm shelter, but its location was not properly communicated to workers, and workers sheltering in a different part of the building were killed in the collapse.

Amazon was criticized for its handling of the event by politicians, media, and advocates. The company was initially unable to compile a list of workers in the building to assist emergency responders, and Amazon founder Jeff Bezos attended a Blue Origin rocket launch the next day before issuing a statement about the collapsed warehouse.

The Edwardsville tornado was part of a large late-season tornado outbreak across the central and southern United States, which caused over 80 deaths in total. A separate tornado in the outbreak destroyed a similarly-constructed industrial building in Mayfield, Kentucky. When the DLI4 facility was rebuilt and reopened in 2024, neither it nor any other facility in the commercial district it was located in had any storm shelters, nor was the new structure of DLI4 built to withstand the extreme winds that the initial tornado produced.

Background In 2016, Amazon announced its intent to open two new e-commerce fulfillment facilities in Edwardsville, Illinois, east of downtown St. Louis. Each of the fulfillment facilities would cover . Amazon's logistics network includes multiple types of fulfillment centers, which contain different machinery depending on the size of the items stored there; the Edwardsville site included one facility for larger items and one for smaller items. After customer orders are packaged at fulfillment centers, packages are transported to smaller delivery stations to be sorted and loaded onto trucks for delivery.

The opening of the two fulfillment facilities was predicted to contribute to the creation of 1,000 full-time jobs for the region, which Mayor of Edwardsville Hal Patton described as a "much-needed employment opportunity" for the area. The facilities are located in the Lakeview Commerce Center, a commercial development site brokered by CBRE Group in Edwardsville. The site also hosted facilities for J.F. Electric, Spectrum Brands, and World Wide Technology by 2020.

The two Amazon fulfillment facilities opened in August 2017, with the building focusing on larger items referred to as STL4 and the one for smaller items as STL6. One year later, in August 2017, the first public tour of STL4 was given to news media, "members of the community", and to federal-level politicians Dick Durbin and John Shimkus. At the time, both facilities combined had over 2,000 employees, over twice as much as projections made the year prior.

In 2018, Contegra Construction constructed the shell of an Amazon delivery station building at the corporate complex, designated DLI4 in Amazon's network. At DLI4's completion in September 2020, the warehouse took up a total of , of which was office space. DLI4 was designed by architectural firm Richard L. Bowen & Associates.

Throughout December 2021, ahead of the Christmas holiday, Amazon's DLI4 site had around 190 employees across all shifts, according to a spokesperson. A majority of the workforce employed at the site were contracted delivery drivers, and expected demand from the holiday prompted the company to increase the number of these contractors. Having fewer full-time delivery workers was part of an initiative at Amazon starting in 2018 to reduce the company's reliance on external carrier services. Only seven full-time employees were at DLI4 at the time of the tornado.

Initial severe weather forecasts

Forecasters at the National Weather Service office in St. Louis, Missouri were tracking a potential severe weather event across parts of Missouri and southern Illinois. A forecast discussion on the afternoon of December 9 outlined that Friday, December 10, would be warm across the region, as a low-pressure system ejecting from the Rocky Mountains would bring in anomalously high dew points and temperatures that, in areas southeast of St. Louis, were forecasted to potentially exceed , in places where low-level cloud cover could dissipate earlier in the day. The system was forecasted to move through the St. Louis office's area of responsibility in the time frame between 02Z and 09Z Saturday, or between 8p.m. Friday through and 3a.m. Saturday, Central Standard Time. Confidence also existed that storms produced by the system could produce tornadoes, and would be moving very quickly.

Forecasters at the Storm Prediction Center in Norman, Oklahoma, were expecting a severe weather event to occur on the evening of December 10. An enhanced risk, the third highest risk the agency issues, was outlined across much of the middle Mississippi River valley shortly before midnight on the 9th. This included St. Louis and surrounding areas, with risks outlined for damaging wind, large hail, and tornadoes. At this time, it was expected that storms across Missouri were going to form after sunset, and would evolve into a squall line, potentially limiting the threat of supercell tornadoes, except for those forming ahead of the line earlier in the evening. It was also noted that, at the time, the HREF forecast model was inconsistent on the location and timing of where storms would form initially.

By the 10th's 1630Z outlook, outlined at 5:08p.m. Central Daylight Time, the St. Louis area remained under an enhanced risk; however, a moderate risk, the second-highest risk applicable, was introduced further south. Confidence was strong that sufficient atmospheric conditions would produce strong tornadoes throughout the day across parts of the middle Mississippi and lower Ohio River valleys.

Onset of severe weather

At 5:20p.m., forecasters at the Storm Prediction Center issued a tornado watch for much of Missouri and parts of Illinois, including Madison County. This watch was effective until 11:00p.m. that night. Seven minutes later, in a mesoscale discussion, forecasters discussed the conditions over the region in greater detail. By this time, storms recently initiated over southwestern Missouri, in the vicinity of Springfield. As atmospheric conditions across the region degraded later on that evening, the threat for severe weather would increase. This discussion specifically outlined an area of eastern Missouri where it was expected that mature storms could interact with an area of supporting atmospheric conditions, producing the region's "best chance for tornadoes". At 7:02p.m., another such discussion detailed how a line of storms was present over central Missouri, some exhibiting features of embedded supercell thunderstorms. One of these storms, with the coldest cloud tops of the line, was directly heading towards St. Louis. This storm was outlined as responsible for an elevated threat of tornadoes and other severe weather, given atmospheric parameters at the time.

That evening, multiple strong tornadoes struck the St. Louis National Weather Service office's area of responsibility. Of these, three were caused by a single supercell. The first of these, rated EF3, touched down at 7:35p.m. and caused significant damage in Defiance, Missouri. Before it lifted at 8:01p.m. west of Bridgeton, Missouri, this tornado resulted in 1 death and two injuries. Five minutes later, at 8:06p.m., a tornado warning was issued for Edwardsville and surrounding areas, as forecasters tracked what was believed to be an ongoing tornado in Bridgeton, Missouri.

As weather conditions began to worsen across the Edwardsville area, one contractor for Boxify Logistics stated that some delivery drivers were told to park in a designated area or return home, with others being instructed to return to DLI4. Another delivery worker recalls talking to dispatcher Kevin Dickey, who would die in the tornado, who asked them to check on weather conditions in surrounding areas, before telling them to "get home safe".

At 8:06p.m. and again at 8:16p.m., the Edwardsville Amazon facilities would receive notice of imminent severe weather through a web application. When the warning was received by DLI4's manager, they alongside an assistant began traversing the warehouse on foot to let other workers know about the storm, and to gather at the site's northern bathroom, which was the site's designated shelter for severe weather. A later investigation determined that a megaphone, which was meant to coordinate such information, was "locked in a cage and not accessible", and that the instructions to "take shelter in the restroom" led to confusion on whether the northern or southern bathroom of DLI4 was the designated shelter. OSHA determined that 10 employees took shelter in a bathroom on the southern side of the building.

The tornado that would strike the DLI4 warehouse, which was spawned by the same parent supercell thunderstorm as the EF3 tornado in Defiance, Missouri, first touched down to the west of the I-270/I-255 interchange at 8:27p.m.

Collapse

Post-event assessments determined that the tornado struck DLI4 at 8:29p.m., with wind speeds estimated at . The tornado struck DLI4's western face, and collapsed the western wall of the warehouse onto the bathroom. The inward failure of the west-facing walls of DLI4 was the first of multiple structural failures across the warehouse as the tornado moved through, including other walls and a large part of the roof. The eastern wall collapsed into a parking lot. Approximately of DLI4 collapsed in total. After this, the tornado moved through DLI4's rear parking lot, from where cars were scattered east of the warehouse. In addition, multiple high-tension transmission towers and overhead power lines were destroyed.The tornado damage survey carried out by the St. Louis National Weather Office determined the EF3 rating from the degree of damage 7, described as "[t]otal destruction of large section of building or entire building", inflicted onto damage indicator 23, Warehouse Building (WHB). DLI4 was struck at the tornado's peak intensity. Throughout the rest of Edwardsville, damage primarily occurred to trees, power infrastructure, and roofs, with a mobile home being destroyed; however, damage was relatively minor and only rated up to EF1. The tornado lifted at 8:32p.m., only being on the ground for 6 minutes; later on, the supercell would produce another long-lived EF2 tornado that struck the community of Bingham and Ramsey State Park.

Fatalities Two of the deceased and the sole non-fatal injury were delivery contractors for Xseed Delivery of Bolingbrook, Illinois. One was a contractor for AB&C D.A.D Inc. of Belleville, Illinois. One was a contractor for Boxify Logistics in St. Louis, Missouri. One was a contractor for real-estate firm CBRE Group who had been assigned to the Edwardsville facility; the only death not inflicted to an outside delivery contractor. All of the deceased were in the building's southern bathroom.