This webpage provides original investigations of collapses and other incidents conducted by the Directorate of Construction, OSHA. Many of these incidents resulted in one or more worker fatalities, and most of them resulted in multi-million dollar property loss, lawsuits, or settlements. Each investigation was performed at the request of an OSHA field office or State Plan OSHA as part of an enforcement inspection. Due to the nature of investigations of construction collapses and other incidents, these reports may contain professional opinions of the investigating engineer, opinions of incident root cause, and factual data and findings.

Our goal is to help employers, workers, construction engineers, project managers, and regulatory bodies identify problems in construction design, project management, and management of field engineering changes. Hopefully, this information will help reduce future incidents, fatalities, and serious injuries.

Some of the photographs, schematics, computations, tables, figures and other non-text items have been removed from the posted versions and are not displayed. The text of each report is otherwise identical with the original document. The original document is a part of the OSHA case file and is maintained in the appropriate Area Office or State Plan.

  • Investigation
    • A pedestrian bridge under construction collapsed and fell over the SW 8th Street near SW 109th Avenue in Miami, Florida. The bridge was being constructed to connect the FIU campus with the City of Sweetwater. The bridge, at this stage of construction, consisted of a single concrete truss spanning approximately 174 feet and weighed approximately 930 tons. The concrete bridge was cast at a nearby off-site location and then transported to its final location. At the time of the collapse, motorists were waiting underneath the bridge for the traffic light. One employee and five motorists were fatally injured, and another employee permanently disabled.
  • Investigation
    • The project involved the reinforcement of the KOZK 1,891-foot-tall guyed communication tower just north of Fordland, Missouri. The tower required structural modifications to support the transmission line replacement. However, the suggested diagonal replacement procedure was flawed in that it compromised the effectiveness of the integrated surrounding braces and the load bearing capacity of the tower legs. At the time of the collapse, contractor was performing structural modifications to the tower.
  • Investigation
    • To repair a damaged or misaligned buried drainage pipe, the employees were hand-digging a trench besides a newly installed concrete barrier, more than 130 feet long. The concrete barrier collapsed into the trench while the employees were digging the trench. Two employees in the trench were killed.
  • Investigation
    • Three employees were engaged in installing a new antenna for a local TV station at the top of a 951-foot tall antenna tower constructed in 2009. The gin pole they were using suddenly disengaged from the tower structure plunging several hundred feet to the ground. The employees were tied to the gin pole and fell with it and were killed. The cause of the disengagement was the failure of attachment between the gin pole and the tower structure.
  • Investigation
    • A Liebherr crawler crane, approximately 570 ft. high, collapsed in lower Manhattan, killing one motorist. The crane operator was attempting to lay down the crane in high wind when the crane suddenly collapsed and overturned. The crane had a luffing jib, 371 ft. long and a 194 ft. long boom. There was no load on either the boom or the jib hooks.
  • Investigation
    • A 12-story steel framed building with concrete floor slabs was under construction and the exterior of the building was to be clad with glass curtain walls. The construction was almost complete on March 23, 2015 when during the disassembly, one of the mast climbing work platforms collapsed. The mast supporting the platform partially collapsed. At the time of the incident, there were four employees on the platform perched near the 9th floor. All four fell to the ground with the falling mast and platform. Three were killed and the fourth fell on the roof of a portable toilet, and suffered severe injuries.
  • Investigation
    • A construction incident occurred on Monday, January 19, 2015 near downtown Cincinnati at approximately 10:30 p.m. when the center and east spans of a ramp bridge being demolished suddenly fell 15-20 feet onto southbound interstate I-75 south freeway, killing a foreman and injuring the excavator operator. At the time of the incident, concrete slab was being removed from the deck of the ramp as a part of the demolition of the Hopple Street Ramp Bridge. The demolition work began a day earlier but had to be stopped due to concerns about some steel girders lifting off their bearings. Work resumed after the remedial measures recommended by the engineers were carried out. Those measures proved inadequate, and the incident occurred.
  • Investigation
    • On November 13, 2014 at approximately 10:30 a.m., a pedestrian bridge under construction at the Wake Technical Community College at the Northern Wake Campus, Raleigh, North Carolina, suddenly collapsed killing a worker. Four employees were injured. At the time of the collapse, concrete was being poured on the metal deck to provide the walking surface. A few hours later, another similar bridge, also under construction, within a block of the first incident, collapsed at approximately 12:30 a.m. in the middle of the following night. No one was injured in the second incident. No construction activities were going on during the second incident. Both bridges were part of the expansion of the Northern Wake campus which was well underway.
  • Investigation
    • During the "Hair Hang Act" at the Ringling Bros. and Barnum & Bailey Circus show in Providence, RI, eight performers were suspended from their hair with their bodies free to dance in a choreographed acrobatic manner. Suddenly, during the act, the metal apparatus supporting the performers plummeted to the floor. Two of the performers sustained critical injuries. In total, there were injuries to nine employees. This incident occurred because the carabiner used to support the performers failed due to being improperly loaded.
  • Investigation
    • On March 25, 2014, two communication towers owned by Union Pacific Railroad (Railroad) collapsed in Blaine, KS, killing two workers. The project consisted of dismantling an older communication tower with all its appurtenances (e.g., antennas, dishes, coaxial cables, etc.). The older tower was located next to a recently constructed tower. At the time of the incident, a gin pole was being raised on the older tower to lower a 10 ft. diameter dish when the rigging of the gin pole suddenly failed causing the 60 ft. tall gin pole to plummet down, resulting in the collapse of both the towers. One employee was situated approximately 20 ft. below the top on the older 250 ft. high tower and was engaged in disconnecting the 10 ft. diameter dish and another employee was on the same tower approximately 80 ft. from the top. One worker died at the scene and the other was pronounced dead at the hospital. There were two additional employees at the site who were not injured.
  • Investigation
    • On February 1, 2014, at approximately 11:37 a.m., a 340 ft.-high guyed telecommunication tower (cell tower), suddenly collapsed during upgrading/construction activities. Four employees were working on the tower removing its diagonals. In the process, no temporary supports were installed. As a result of the tower's collapse, two employees were killed and two others were badly injured. The cell tower fell onto the guy wires of an adjacent smaller cell tower and caused it to collapse, killing a firefighter while he was rescuing the injured employees on the ground. The collapse of the smaller tower is not covered in this investigation.
  • Investigation
    • On November 2, 2013, at approximately 1:30 p.m. an incident occurred at the construction site of the runway expansion project of Ft. Lauderdale-Hollywood International Airport when five precast concrete beams fell off their bearings, and an additional five beams slid off their bearings but remained over the concrete bents. The beams fell some 25 feet onto the railroad tracks owned by Florida East Coast Railways which operates trains multiple times a day hauling commodities across Florida. The beams were placed just a couple of days earlier and were to support the actual runway consisting of a post-tensioned concrete slab. One employee sustained minor injuries but the potential for multiple fatalities was very obvious.
  • Investigation
    • On November 13, 2013 an incident occurred at the construction site of a parking garage in Ft. Lauderdale, FL, where two precast walls weighing about 34 tons each suddenly fell. The walls were erected less than an hour before they fell. Two employees sustained injuries although this incident could have resulted in multiple fatalities. The parking garage was being constructed as a part of a larger project to construct new rental apartment buildings. The entire complex was called RD Flagler Village.
  • Investigation
    • On May 28, 2013, a construction incident occurred at the site of Verizon Wireless cell tower in Georgetown, MS. The 300 ft. high cell tower was being equipped with a gin pole to replace the old antennas with new ones. While the gin pole, approximately 40 ft. tall was being raised, the rigging of the gin pole block suddenly failed, killing two workers located on the tower.
  • Investigation
    • An incident occurred on March 31, 2013 inside the turbine building of Unit 1 at the Arkansas Nuclear One power plant in London/Russellville, AR. During the scheduled refueling outage of Unit 1, it was pre-planned to replace the turbine stator. While the old turbine stator was being removed and transported to the trailer deck, the temporary overhead crane supporting the old stator suddenly failed and collapsed, killing an employee. Eight other employees were injured. The turbine stator weighed over a million pounds.
  • Investigation
    • On September 6, 2012 at approximately 5:00 a.m., a partial collapse of the second level slab occurred during construction of the 159-room, ten-story building, Hyatt Place Hotel in Omaha, NE. At the time of the collapse, the northwest section of the second level was being placed with fresh concrete over the formwork. Twenty-five employees were working with the wet concrete. Six of them on the formwork fell 10 to 18 feet below to the ground level. Three employees were injured.
  • Investigation
    • A mast climbing platform partially collapsed at a 21-story concrete framed condominium building under construction. The mast and one half of the platform remained intact. Immediately before the incident, the platform descended from the 13th floor and stopped at the 11th floor when one half of the platform suddenly separated from the main frame (motorized unit) and fell to the seventh floor. Three workers were killed.
  • Investigation
    • The crane was assembled at the site with a 420' boom, 240' mast, 61' spar and 836,000 pounds of main counterweight attached to the spar. An additional 836,000 pounds of auxiliary counterweight was to be attached to its pendants suspended from the mast tip at 105' from the axis of the crane. With this configuration, the crane would have a million pound lifting capacity at a maximum boom radius of 160'. The incident occurred during the installation of the auxiliary counterweight. Four workers were killed and 6 injured.
  • Investigation
    • A new medical office building was under construction when the long span wood roof trusses collapsed. The workers erected the trusses a few hours before and were installing temporary and permanent bracings and purlins at the time of the incident. Shortly before the incident, three bundles of 2x6s to be used as purlins and braces were placed over the top chord of the center trusses. Two workers were seriously injured.
  • Investigation
    • Two construction workers fell twenty stories to the ground and died when the stripping platform they were working on failed. The incident occurred during the construction of a 22-story condominium building. The platform was supported on structural framing resting on the 19th floor concrete slab and on the underside of the 20th floor slab. There were three other employees on the platform at the time of the failure, but they were able to hang onto the railing and the net, and were rescued.
  • Investigation
    • The project consisted of construction of a large, one-story concrete and steel structure for an indoor swimming and diving pool with bleachers. The roof trusses were curved and spanned 190 feet and weighed approximately 80,000 pounds. The incident involved the collapse of three long span steel roof trusses and several steel bar joists that fell approximately 50 feet to the ground. Two workers were killed, 2 injured.
  • Investigation
    • The project consisted of ten 3-story buildings to construct 82 townhouses. Tunnel forms were used by the construction team for casting concrete on the floors and in the walls. The incident occurred while concrete was being poured on the third floor of one building. A portion of the building collapsed killing two workers and injuring three others. The building was approximately 53 ft. wide and 150 ft. long.
  • Investigation
    • The 1,000 ft. guyed tower was being modified to add a new HDTV antenna and additional equipment. Installation of horizontal braces and replacing the top 14 ft. with a new 6 ft. tower section were to be undertaken. The crew had positioned a track and a gin pole on one face of the tower as a means to hoist the new antenna. The load line was attached to a block on the tower some thirty feet above the base. As the load line was tensioned, the tower collapsed killing three employees.
  • Investigation
    • Two 142 ft. high scaffold towers collapsed, killing five workers and injuring 10 others. The towers were erected to provide a working platform for the facade renovation of a 1914 era 20-story steel framed masonry building. The face bricks and steel window lintels had already been removed from the 6th to the 14th floors and the cement plastering work was being done. At the time of the incident, two workers were manually hoisting a cement bag to the top of the scaffold tower.
  • Investigation
    • The project consisted of fabrication and erection of structural steel framing consisting of round steel pipes to support two billboard signs, on the two opposite faces, each weighing approximately 5,400 pounds. The workers engaged in electrical and bill board installation were finishing the newly erected sign. The billboard structural framing suddenly collapsed killing all three workers and crushing the cars parked below.
  • Investigation
    • The project consisted of construction of a six-story parking garage. The 55-foot long mast climbing platform consisted of 20 foot fixed platform plus extensions on either side supported in the center by a single mast. Three sections, each 5-foot long were installed on one side, and four sections were installed on the other side. The side, which had four sections collapsed. 3 workers were injured.
  • Investigation
    • A steel structure under construction 176 ft. x 312 ft. and 130 ft. high collapsed at the construction site for the Olympic Aquatic Center in Atlanta, Georgia. The structure, was an addition to the existing pool structure. Just prior to the collapse, the steel erection crew had erected a steel frame and a pair of steel joists spanning 176 ft. from an existing structure to the erected steel frame. The failure occurred within 15 to 30 minutes after the crane was released from the paired joists. The incident did not result in any injuries.
  • Investigation
    • The building project under construction was a 31-story condominium complex. Five employees were applying stucco to the fascia walls when the platform of a mast climbing work platform (scaffold) collapsed. Three employees were on a modified cantilever deck section, which was connected to platform extensions attached to the main platform. The cantilever deck failed and as a result, the three employees fell about 75 feet where they were fatally injured. The other two employees working on the platform, were able to grab and hold on to the structure, and sustained only minor injuries.
  • Investigation
    • A 350 ft. high guyed radio transmission tower collapsed during the final phase of its construction. Three FM antennas were already hoisted and fastened to the top sections of the tower. On the day of the incident, two workers positioned near the top section of the tower were beginning to lower the gin pole from the top section of the tower to the ground. The gin pole suddenly dropped and struck the coaxial cable, followed by the collapse of the tower. Both workers, who were tied to the collapsing tower, fell to the ground, resulted in the death of one worker and serious injuries to the other. The tower structure consisted of 25 pre-fabricated steel sections, each 10 ft. or 20 ft. in height.
  • Investigation
    • A pile top drill unit and a 206 feet long pipe casing, 68-inch diameter suddenly dropped 25 feet into the soft ocean sediment bed as the crane of the jack-up barge was releasing a 80 ton bottom hole assembly onto the platform of the drill unit. The fall of the drill unit caused injuries to three employees working on the platform. One of them was fatal. The steel casing was horizontally held above sea level by the jack-up barge, which was supported on four legs, each 7.5 feet square in cross-section.
  • Investigation
    • A construction worker was killed and two workers were injured when their work platform, about 230 ft. above ground, was struck by a collapsing steel post, during the erection of the roof cable structure at the Georgia Dome in Atlanta, GA. The workers were in the process of hoisting the center truss in position to make the final connection of a diagonal cable to the bottom joint of the center truss. The construction workers were using hydraulic pumps to apply loads to the temporary jacking strands in order to make the permanent diagonal cable connection to the center truss.
  • Investigation
    • The structural steel support system of an open excavation, 150 ft. x 208 ft. by 47 ft. deep collapsed causing a cave-in of several thousand cubic yards of soil. The excavation was done for the construction of a 12-story office building with four levels of underground parking. The collapse caused the internal support system to slide and fall into the open excavation. At the time of the incident, construction had stopped for the day and therefore did not cause any death or injury, though it had significant potential for casualties.
  • Investigation
    • A tower crane collapsed in the center of the financial district in San Francisco, California. Four construction workers engaged in the climbing operation of the crane and one person on the street below the crane were killed. The SN 355 model crane, a climbing, luffing boom tower crane had a maximum reach of 192 feet and a maximum lift capacity of 17,000 pounds with two wire ropes. The height of the crane on the day of collapse was 298 feet and consisted of 15 identical sections added at different stages. On the day of the incident, climbing process was underway to add another tower section.
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Only selected reports are posted on this webpage. For assistance with any of the reports, figures or illustrations, please contact the Directorate of Construction at (202) 693-2020.
Highlights
  • OSHA finds that structural engineers must specify the order and manner of replacing existing diagonals and strut members of cellular towers. Onsite judgement by workers engaged in retrofit of towers has often proven to be disastrous. (October 2018)
  • OSHA finds that the contractors and engineers should consider turbulent winds causing uplift and vortex in areas exposed to tropical storms and hurricane. OSHA recommends analysis based on Computational Fluid Dynamics (CFD) calculations. (September 2018)
  • OSHA finds that the contractor not laying the boom and jib in the face of impending wind in accord with the crane manufacturer's instruction caused the collapse of the crane. (July 2016)
  • OSHA finds that contractors must exhibit abundance of caution and supervision during dismantling of mast climbing platforms, not to overload the platforms causing failure of the mast. (August 2015)
Additional Information