Fangxiao Liu, Ph.D. Candidate (Construction), The Pennsylvania State University

KEY WORDS: CONSTRUCTION ACCIDENTS, WORLD TRADE CENTER, FAILURES CASE STUDIES

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Fig.1 A Crane Accident in New York, 2008 (Source: http://www.hbsafety.cn/article/news/6/200803/40042.shtml)

Introduction

In the construction industry, owners, contractors and designers have the obligation to provide a safe site working environment, and their negligence on safety may cause severe accidents and injuries as well as economic loss (Laufer, 1987). A large number of construction accidents are reported and thousands of workers are killed or injured on construction sites each year. As a result, project owners lose large amounts of money and many families suffer from permanent pain. In 2012, there were 4 accidents that occurred on the World Trade Center (WTC) construction project, which serves as a case study to learn about construction accidents.

Common Types of Construction Accidents

There are many types of construction accidents, and they can be classified by different categories. In terms of severity, a construction accident may or may not cause injuries and life loss, and the economic loss may be small or huge. A construction accident can be rooted in equipment failure, design ignorance, working carelessness, and natural disasters, etc. In addition, based on the locations, there are tunnel accidents, highway construction accidents, and residential building site accidents, to name but a few. Table 1 shows some examples of construction accidents (URL 1).

Table 1. Classification of Construction Accidents

Classification Category
Labor Type
Project Type
Heavy Equipment
Building Component
Others
Accidents Examples
  • Painter Accidents
  • Plumber Accidents
  • Iron Worker Accidents
  • Brick Layer Accidents
  • Carpenter Accidents
  • Maintenance Worker Accidents
  • Union Worker Accidents
  • Etc.
  • Tunnel Accidents
  • Excavation Accidents
  • Highway Construction Accidents
  • Residential Building Site Accidents
  • Bridge Accidents
  • Parking Garage Collapse
  • Demolition Accidents
  • Etc.
  • Crane and Truck Accidents
  • Welding Equipment Accidents
  • Ladder Accidents
  • Scaffolding Failure
  • Elevator Accidents
  • Power Tool Accidents
  • Cable and Rope Accidents
  • Forklift Accidents
  • Saw Blade Accidents
  • Etc.
  • Ceiling Collapse
  • Wall Collapse
  • Stairs Failures
  • Window Installation Failure
  • Slab Failure
  • Etc.
  • Falling Object Accidents
  • Fire and Explosions
  • OSHA Violations
  • Etc.


Key Factors Leading to Construction Accidents

Construction accidents can be caused by a variety of reasons, and different disciplines involved in a construction project may all be responsible. In the planning phase, owners may fail to consider potential site safety issues, and pay little attention to safety management. In the design phase, designers and architects may neglect all possible safety-related design codes or not be able to eliminate all possible factors. In the construction phase, contractors may fail to be cautious about site safety risks or report problems in time, and workers may do their job carelessly.
The following is a video clip from OSHA about "Struck-by Accidents in Construction/Swinging Cranes":


The most common causes of accidents in construction projects are (Haslam, et.al., 2005; URL 6):

-Falling Hazards
Falling accidents typically occur when a worker steps to or backwards an open-sided floor or slab and focuses on the work. Slips, trips and low falls are the most common forms, and usually cause minor injuries (e.g. musculoskeletal disorders, puncture wounds, etc.). By contrast, fatal accidents can be caused by falls from height, and in most cases workers suffer from head or shoulder wounds. Lack of opening protections, inadequate edge protections, scaffolding failures, and inappropriate use of ladders may lead to potential falling hazards.
-Unsafe Working ConditionsAccording to Abdelhamid, T. and Everett, J. (2000), an unsafe condition is “a condition in which the physical layout of the workplace or work locations, the status of tools, equipment, and/or material are in violation of contemporary safety standards”. Unsafe conditions on a construction site include exposed rebar, uncovered holes or trenches, and inadequate personal protective equipment, etc. Accidents can be caused by failing to identify an unsafe condition, ignorance of an unsafe condition reported by workers, or deciding to act unsafe in the work environment.
-Struck By Tools, Equipment and Falling ObjectsSerious injuries may be caused by falling objects or tools, which are due to lack of tool belts, inadequate site storage planning, and lack of toe boards on scaffolding. In addition, improper use of construction vehicles and equipment (e.g. cranes, hoists, trucks, etc.) may also result in struck, crushed or trapped accidents.
-Trenching and Excavation HazardsTrenching hazards may set workers in danger of being trapped by soil and rocks, asphyxiation, inhalation of poisoning fumes and drowning in underground water. Inadequate excavation wall support, protective system failure, soil inspection failure and unsafe passage into and out of the trench may generate such kind of construction accidents.
-Stepladder MisuseThe majority of falls in construction accidents are due to stepladder misuse or failures. Ladder injuries include loss of balance, improperly ladder setting up, loss of balance, and exceeding the ladder weight capacity, etc. Information on the causes of ladder injuries, ladder types, ladder misuse and safe ladder practices can be found in the document of “Ladder Safety in Construction” developed by Washington State Department of Labor & Industries.
-Electrocutions and Power Tool AccidentsElectrocutions can be caused by body contact with power cables, cable strikes on underground utilities, or defective of ground-fault protection. Power tool accidents, such as nail gun injuries, are usually caused by inappropriate use or inadequate eye protection. Furthermore, improper guards in place on power tool management may lead to more severe injuries.
-Scaffolding AccidentsScaffolding accidents cause large numbers of deaths and injuries every year. Most accidents are caused by scaffold equipment failure, inadequate scaffolding safety training, lack of personal fall protective systems, or improper scaffolding equipment operation. In addition, materials and tools falling off scaffolding may also cause injuries.
-Construction Vehicle AccidentsLarge construction equipment (e.g. cranes, forklifts, dump trucks, road graders and concrete mixtures, etc.) may become potential dangers on a construction site. Due to their weight and size, workers and drivers can be seriously injured or killed in an accident. In some cases, drivers may not have competent driving skills, or their visibility may be limited due to site constraints (URL 8).

The Role of OSHA

The Occupational Safety and Health Administration (OSHA) is an agency of the Department of Labor (URL 7). It was created by the Congress with the Occupational Safety and Health Act of 1970 with the aim to “assure safe and healthful working conditions for working men and women by setting and enforcing standards and by providing training, outreach, education and assistance”. OSHA is responsible to inspect construction sites, investigate construction accidents, and enforce standards and regulations to reduce construction accident impacts. In 2011, 40,648 federal inspections and 52,056 state inspections were carried out with the budget of $573,096,000.

Organizational Chart

The organizational structure of OSHA can be found in the following document "OSHA Organizational Chart".

OSHA Law & Regulations

Pic 2-OSHA Statistics in 2011.png
Fig.2 "Fatal Four" Defined by OSHA

In 1970, the Occupational Safety and Health Act (OSH Act) became federal law and has been enforced by OSHA in every state in the US. Under the OSH Act and other regulations (standards), employers are required to provide a safe and healthful working environment and prevent workers from hazards and dangers in the working place.

"Fatal Four"

According to OSHA, 4,609 workers were killed on the job in 2011 (almost 90 deaths every week or 13 deaths every day), out of which 721 workers (17.5%) were killed in construction. The leading causes, also called “Fatal Four” of construction accidents in 2011 are falls, electrocutions, struck of object, and caught-in/between (Figure 2). Three out of five construction worker deaths (410 workers’ lives in total) in the US were caused by the “Fatal Four”.

Top 10 Most Frequently Cited OSHA Standard Violations

According to OSHA, the top 10 most frequently cited OSHA standards violated in 2011 are:
o Hazard communication standard, general industry (29 CFR 1910.1200)o Respiratory protection, general industry (29 CFR 1910.134)o Scaffolding, general requirements, construction (29 CFR 1926.451)o Fall protection, construction (29 CFR 1926.501)o Control of hazardous energy (lockout/tagout), general industry (29 CFR 1910.147)o Electrical, wiring methods, components and equipment, general industry (29 CFR 1910.305)o Powered industrial trucks, general industry (29 CFR 1910.178)o Ladders, construction (29 CFR 1926.1053)o Electrical systems design, general requirements, general industry (29 CFR 1910.303)o Machine guarding (machines, general requirements, general industry) (29 CFR 1910.212)

Case Study - WTC Accidents

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Fig.4 Crane Accident Location (Source: Google Map)

Pic.3 WTC - Copy.JPG
Fig.3 WTC Construction Site
3 World Trade Center and 4 World Trade Center (Figure 3 & 4), part of the World Trade Center reconstruction in New York City, were designed by Kenneth Gardner and Herbert Belton. 3 World Trade Center will provide 2.8 million square feet of working space, and is schedule to be completed by 2014. 4 World Trade Center is designed to offer 1.8 million square feet of office space, and will be completed by 2013. Since the beginning of 2012, four accidents at the World Trade Center construction site have been reported, among which 3 were on the Tower 4 site and 1 was on the Tower 3 site.

Tower 4 Construction SiteSeveral steel beams (20 ton) fell 40 stories and crushed a truck on February 16 with no injuries reported (Figure 5). The accident occurred in the morning when a crane was lifting metal beams to the top of Tower 4. The cables in the crane snapped suddenly and dropped three 62-foot-long beams (appropriately 20 tons) near Church Street and Cortlandt Street. As a result, the load fell 40 stories from the crane onto a flatbed truck. Luckily no one was seriously injured in this accident, and only one worker got checked for minor injuries. Service for the 1 train was also delayed. (URL 9)
On June 26th, a 37year-old worker was impaled by a piece of rebar after a 5-feet fall (URL 5). The man lost his balance when working to the top of Tower 4 and the falling force made the piece of rebar that he was holding straight through his stomach. His liver was bruised and two of his ribs were fractured. This accident belongs to the “slips, trips and low falls” type but has led to serious injuries.
The next day (June 27th), shattered glass caused by a tilted crane fell from the 54th floor onto Liberty Street (URL 3). A steel beam smashed some windows due to a sudden gust of wind and the glass pieces of 2 windows fell down. Thanks to the closure of the street and the protective shed over the pedestrian sidewalk, no injuries were reported.
Pic 5-Crane Accident in Tower 4.jpg
Fig.5 Crane Accident in Tower 4 (Source: http://yibada.com/news/view/21318586/)

On the Tower 3 Construction Site, a worker was seriously injured after falling 15 feet to the ground while installing a beam in the afternoon on August 29th, 2012 (URL 4). The 36-year-old man was from Falcon Steel Co., Inc., Wilmington, Del and suffered serious arm and head injuries. He was working at the base of Tower 3 in the afternoon when he slipped and fell onto the ground.
Table 2. WTC Accidents Summary in 2012

Date
Location
Discription
Accident Type
Injuries
Feb.16, 2012
Tower 4 Site
Crane Cable Failure
Heavy Equipment Accident
1 worker received minor injuries.
Jun.26, 2012
Tower 4 Site
Worker Impaled by rebar
Falling Hazards
1 worker was seriously injured.
Jun.27, 2012
Tower 4 Site
Glass Falls
Falling Hazards
No injuries were reported.
Aug.29, 2012
Tower 3 Site
Worker Falls
Falling Hazards
1 worker was seriously injured.

Similar Case-UW Demolition Accident
On July 21th, 2012, a large concrete slab fell and crushed onto the cab of a crane on the University of Washington campus. The slab was 15 feet by 30 feet and fell six stories onto the crane, trapping the operator inside the cab with severe injuries. It took about 2 hours for the emergency crews to free him and then he was rushed to the hospital. The operator was working to demolish a residential building on the campus at the time of being injured. Figure 6 below was taken at the accident site.

Pic 5-Crane Accident in UW.jpg
Fig.6 Crane Accident at the UW campus (Source: http://www.craneaccidents.com/2012/07/report/crane-operator-criticaly-injured-in-uw-construction-accident/)


Lessons Learned

In Case of a Construction Accident

All parties must react to a construction accident immediately, and take measures to minimize the impacts of injuries and economic loss (URL 2). The most important thing is to give prompt medical care to injured workers and ensure the safety of other on site workers. Project managers need to contact owners in time, and coordinate with designers for best solutions. It is also important to preserve and investigate the site immediately, as well as reporting to OSHA. A post-accident meeting should be coordinated by all related parties and measures need to be taken to prevent similar accidents in the future.

Prevention and Constructability

In 1986, the Construction Industry Institute (CII) defined “Constructability” as “the optimum use of construction knowledge and experience in planning, design, procurement, and field operation to achieve overall project objectives”. Safety should be paid the first attention throughout the whole project process, and it is one of the most important components of constructability.

Construction accident prevention involves all related parties and requires the collaboration of all disciplines in a project (Chi, et al., 2005; Gyi, et al., 1999). The implementation of accident prevention should be embedded throughout the planning, designing, construction and maintenance phases. A safety plan should be well developed based on the specific project conditions in the planning phase, and agreed by all parties involved in the project. In the design phase, designers and engineers should take safety in the first place. According to Behm (2006), designing for safety is “the consideration of construction site safety in the preparation of plans and specifications for construction projects”. All potential hazards in the site should be identified and minimized prior to the installation of protective systems. During the construction and maintenance phases, everyone on the site must follow OSHA law and regulations, and any violations should be documented and reported. All the workers should be trained for safety concerns, and they should use protective equipment or tools when working in dangerous zones. General contractors and engineers should provide and maintain a clean and safe working environment. All safety equipment and systems on the site should also be supervised and maintained regularly.


Conclusion

Construction accidents cause a large number of deaths, injuries and economic loss each year. They can be classified into different categories, and the leading causes are falling hazards, unsafe working conditions, and scaffolding accidents, etc. In the US, OSHA is responsible to inspect construction sites, investigate construction accidents, and enforce standards and regulations to reduce construction accident impacts. They have made OSHA law and regulations and enforced them in every state. Thanks to the work of OSHA, fatalities at workplace have been reduced by over 65 percent and injuries have been reduced by 76 percent since 1970. In terms of construction accident prevention, owners, contractors and designers need to collaborate efficiently throughout the lifecycle of a project and all efforts should be taken to eliminate the possibility of an accident. The concept of constructability should be embedded early in the design phase to minimize the impacts of accidents.

Annotated Bibliography

Abdelhamid, T., Everett, J. (2000). Identifying Root Causes of Construction Accidents. Journal of Construction Engineering and Management. 126, Pages 52–60.
  • Three root causes of construction accidents are identified by using the accident root causes tracing model (ARCTM).

Behm, M. (2006). An Analysis of construction Accidents from a Design Perspective. The Center to Protect Workers' Rights. http://www.cpwr.com/pdfs/pubs/research_pubs/krbehm.pdf (Oct 1, 2012).
  • This report analyzes construction accident issues from the design perspective and provides an investigation model.

Bernard, K. EzineArticles. <http://ezinearticles.com/?9-Common-Causes-of-Construction-Accidents&id=3202446> (Dec 2, 2012) (URL 6)
  • Nine common causes of construction accidents are discussed in this article.

Block O'Toole & Murphy: <http://www.blockotoole.com/>(Nov.15, 2012) (URL 1)
  • A thorough introduction of construction accidents can be found on this website.

Breakstone, White & Gluck. <http://www.bwglaw.com/> (Dec 2, 2012) (URL 2)
  • Information regarding with how to deal with a construction accident can be found on this website.

Chi, C., Chang T., Ting H. (2005). Accident patterns and prevention measures for fatal occupational falls in the construction industry, Applied Ergonomics, Volume 36, Issue 4, Pages 391-400.
  • Different measures to prevent fatal falls and accidents at construction sites are discussed.

Conley, K. (June 27, 2012). Crane tilt causes glass to fall from 54th floor of 4 World Trade Center. New York Post. <http://www.nypost.com/p/news/local/manhattan/crane_tilt_shatters_glass_center_dG6lHJknuZ5c5C3sxGWSzL> (October 2, 2012) (URL 3)
  • This article documented the construction accident of falling glass at the Tower 4 site (with photos).

Gyi, D.E., Gibb, A.G.F., Haslam, R.A. (1999). The Quality of Accident and Health Data in the Construction Industry: Interviews With Senior Managers. Construction Management and Economics 17, Pages 197–204.
  • This paper describes the quality of accident data using interviews with managers from nine large engineering companies, and explores the methods to integrate the management of health and safety performance.

Haslam, R.A., Hide, S.A., Gibb, A.G.F., Gyi, D.E., Pavitt, T., Atkinson, S., Duff, A.R.. (2005). Contributing factors in construction accidents, Applied Ergonomics, Volume 36, Issue 4, Pages 401-415.
  • By analyzing findings from previous researches on over 100 construction accidents, several factors that may lead to construction accidents are identified.

Hawkins, E.B.(2012). "Impaled At WTC: Construction Worker Suffers Injury At 4 World Trade Center." The Inquisitr. <http://www.inquisitr.com/264206/impaled-at-wtc-construction-worker-suffers-injury-at-4-world-trade-center/> (October 2, 2012) (URL 5)
  • The construction accident of the impaled worker at the Tower 4 site is described by the author.

Laufer, A. (1987). Construction accident cost and management safety motivation, Journal of Occupational Accidents, Volume 8, Issue 4, Pages 295-315.
  • The author explores the relationship between the safety management motivation and the firm's economical interests, and indicates recommendations of practical implementations for safety management.

Occupational Safety and Health Administration. <http://www.osha.gov/> (Dec 1, 2012) (URL 7)
  • Homepage of OSHA.

Rosen, E.D.. (August 29, 2012). Construction Worker Injured at 3 World Trade Center. Commercial Observer. <http://commercialobserver.com/2012/08/construction-worker-injured-at-3-world-trade-center/> (October 2, 2012) (URL 4)
  • The construction accident of the falling worker at the Tower 3 site on August 29, 2012 is reported in the article.

Washington State Department of Labor & Industries. <http://www.lni.wa.gov/> (Dec 1, 2012) (URL 8)
  • A lot of construction safety training materials can be found on this website.

Wingate, Russotti, Shapiro & Halperin, LLP. New York Injury Talk Blog. <http://www.nyinjurytalk.com/construction_accident/> (Dec 2, 2012) (URL 9)
  • The crane accident in WTC Tower 4 in Feb.21, 2012 was documented in this article