Workplace Injury, Illness and Death- How do we know how many?

Posted on by Kerry Souza, ScD, MPH


Workers Memorial Day, April 28, is a day to reflect on how work-related injuries, illnesses, and deaths affect American workers, their families and society at large. Each year at this time NIOSH reports on the burden of workplace injury and illness (see MMWR).

But how do we know how many workers died or suffered from work-related injuries and illnesses? Research tells us that work-related injuries and illnesses are consistently undercounted, and that some estimates are flawed or biased. How good are the numbers and what is being done to produce better data? 

To answer those questions we need to understand the purposes and methodologies of current systems, identify the needs for surveillance data that aren’t being met, and determine how to close those gaps.

Considering fatal work-related injuries first, that annual statistic is from the Bureau of Labor Statistics (BLS) Census of Fatal Occupational Injuries (CFOI) program. CFOI uses multiple sources of data, including death certificates and even news articles, to identify each case* of fatal work-related injury.   CFOI is considered a robust system for identifying cases of fatal injuries. In 2014, 4,821 U.S. workers died from work-related injuries.

Counting other outcomes is more difficult.

It is well known that deaths from work-related illness are poorly counted.  Very little data is available, so producing an estimate requires complex modeling. The last estimate available was produced by Dr. J Paul Leigh; he estimated that, in 2007, 53,445 fatal illnesses could be attributed to workplace exposures.

There is no comprehensive system for counting non-fatal outcomes – either illness or injury. The primary US system for counting non-fatal work-related injuries is the BLS Survey of Occupational Illnesses and Injuries (SOII),which uses injury data reported by a sample of US employers to produce annual estimates for the country and for most states.  For 2014, SOII estimated approximately 3 million nonfatal injuries and illnesses to private industry workers and 722,000 to state and local government workers. By design, SOII was not created to monitor all work-related injuries. In addition, researchers have shown that SOII has weaknesses that result in undercounting of some work-related injuries.

As with fatal work-related illness, non-fatal work-related illnesses are often not identified and documented by our health system. (SOII includes some cases of work-related illness reported by employers, but not a good source of statistics on work-related illnesses).  Federal (including NIOSH), state and other entities monitor and produce estimates for select work-related illnesses. While each program produces valuable data, this set of programs is by no means a comprehensive surveillance system.

Gaps in the occupational public health surveillance system mean that it’s not currently possible to document the full burden of work-related injuries and illnesses to American workers. But the good news is that occupational public health professionals at the federal, state and community level are working to improve systems and provide better information.  Recently, NIOSH and BLS engaged The National Academies of Science, Engineering and Medicine (NASEM) to provide recommendations for the most effective and efficient occupational health surveillance systems.  Later this year, NASEM will convene a panel of experts to address the topic of “Developing a Smarter National Surveillance System for Occupational Safety and Health in the 21st Century “Developing a Smarter National Surveillance System for Occupational Safety and Health in the 21st Century””. Look for updates from NIOSH on this NASEM study later this year.

Workers Memorial Day neither begins nor ends with counting occupational injuries and illnesses. But it is a good opportunity to reflect on what we know about the toll of these injuries and illnesses, and how we can improve our data.

In honor of Workers Memorial Day, we are posting a week of blogs. Please check back daily and contribute to the conversation.


Kerry Souza, ScD, MPH   

Dr. Souza is an epidemiologist in the NIOSH Division of Surveillance, Hazard Evaluations and Field Studies


*A system that intends to count each and every member of a group is called a census.


References and Resources


Rosenman KD, Kalush A, Reilly MJ, Gardiner JC, Reeves M, Luo Z. How much work-related injury and illness is missed by the current national surveillance system? J Occup Environ Med. 2006;48:357-365.

US Bureau of Labor Statistics, Research on the Completeness of the Injury and Illness Counts from the Survey of Occupational Injuries and Illnesses at:

Boden LI. Capture-recapture estimates of the undercount of workplace injuries and illnesses: sensitivity analysis. Am J Ind Med. 2014 Oct;57(10):1090-9. doi: 10.1002/ajim.22247. Epub 2013 Sep 10.

Azaroff LS1, Levenstein C, Wegman DH. Occupational injury and illness surveillance: conceptual filters explain underreporting. Am J Public Health. 2002 Sep;92(9):1421-9.

Shire JD, Marsh GM, Talbott EO, Sharma RK. Advances and current themes in occupational health and environmental public health surveillance. Annu Rev Public Health. 2011;32:109-32. doi: 10.1146/annurev-publhealth-082310-152811.

Spieler EA and Wagner GR. 2014. Commentary: Counting Matters: Implications of Undercounting in the BLS Survey of Occupational Injuries and Illnesses. AJIM 57:1077-1084



Note: An important component of this surveillance is the NIOSH-funded state-based surveillance program, which funds health departments in 26 states to conduct occupational health surveillance and intervention activities. State programs monitor work-related outcomes most relevant to their state; data from multiple states is sometimes aggregated to produce regional estimates or get closer to a national estimate.




Posted on by Kerry Souza, ScD, MPH

3 comments on “Workplace Injury, Illness and Death- How do we know how many?”

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    Dear Dr. Souza,

    Thanks for your helpful post during this important week to remember the workers and their families and friends who, mostly, quietly bear the burden of these deaths, injuries and illnesses and suffer out of the public eye.

    This blog asks such an important question: how accurate are these numbers for non-fatal exposures. The MMWR investigation referenced occurred because a report or an incident was received: how many employees fear that they might lose their job if they complain about a product or situation that is affecting their health? Would NIOSH or other body consider an anonymous hot line for workers to use? Yes, there would be some background noise of employees who have an issue with their employer that is not truly work related, however the hotline might bring to light issues long before there are a significant number of complaints, or help draw attention to complaints from around the country. I previously came from a unionized background, where our safety stewards would take an issue forward for discussion, and have avenues to pursue. Many work sites have lost this reporting mechanism (although committees might be in place, there is still fear of retribution). I would be very interested in other’s thoughts on this.

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Page last reviewed: April 13, 2021
Page last updated: April 13, 2021