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Injuries, Illnesses, and Fatalities

Occupational Injuries and Illnesses Classification System (OIICS), Version 3.0

Summary of Major Changes


The Occupational Injuries and Illnesses Classification System (OIICS) was developed by the Bureau of Labor Statistics in 1992 to code detailed injury, illness, and fatality data. The structure was originally developed for use with BLS’s Survey of Occupational Injuries and Illnesses (SOII) and the Census of Fatal Occupational Injuries (CFOI). OIICS was based on the International Classification of Diseases (ICD-10) but updated to allow for more flexible coding and to provide more detailed coding options for surveillance and research purposes. Since its debut, the system has been adopted by a number of other safety and health organizations, academic researchers, Workers’ Compensation programs, and other members of the occupational safety and health community.

A major planned update to OIICS was released in 2012. This version, known as OIICS v 2.01, was implemented with reference year (RY) 2011 data and the series will continue through RY 2022, resulting in a 12-year series.

BLS has now completed the second major update to OIICS, known as OIICS version 3.0. This revision was begun in 2018 with the original goal to implement the updated system with reference year (RY) 2021 data. The implementation of OIICS 3.0 was delayed in order to accommodate planned series breaks in industry with the North American Industry Classification System (NAICS) and occupation with the Standard Occupation Classification (SOC) system. This series break will also mark the transition to two-year estimates for the SOII, which is anticipated to reduce respondent burden while allowing for the publication of more detailed estimates. This means that OIICS 3.0 will be implanted with RY 2023, set for publication in Fall 2024.

Revision Goals

At the beginning of the revision process, the team put out a request to stakeholders as well as a Federal Register Notice to the general public asking for comments on OIICS version 2.01 and asking for suggestions for the revision. Over 400 comments were received. Based on this feedback, the team developed three major goals.

  1. Improve quality of collected data

  2. Improve manual use experience for coders

  3. Align codes with current priorities of data users

Decisions and changes were made with these aims in mind. Major changes are listed below.

General Changes for Improved Data Quality and Manual Ease of Use

Updated format: The OIICS 3 manual is now primarily formatted as a spreadsheet for ease of reference, which helps improve coder consistency. Information is now organized into separate columns for:

    • Numeric OIICS Code

    • Code Title

    • Includes - Examples and common terms for items included in the code

    • Excludes - Items that would not be classified using the code in question, including a reference pointing the user to where to find the appropriate code

    • Code interactions - This notes coding rules or dependencies to provide guidance on selection of codes from other OIICS fields that are dependent on choice (See below)

General rules of selection: These have been organized onto a separate, accessible tab for each coding structure (i.e. nature, part, etc.). These are general rules that affect that entire structure. Each tab contains guidance for how to code when there are multiple applicable options, as well as any special considerations for that structure. For example, Source and Secondary source rules of selection contain rules for when to select part of object versus whole object. Rules of selection that affect a single code or group of codes are now found with that specific code/group in ‘Code Interactions.’

Code-interaction rules of selection: In addition to general rules of selection, the manual also now places rules of selection that apply to only a single code or group of codes with that code in the manual. These are found in the ‘Code interactions’ column. This explains codes that must be used together, for example, the Nature of injury often informs the Part of body that must be choses, or in all cases, the coded Event informs the Source and Secondary source. For example: for ‘Nature 111* - intracranial injuriesselect ‘Part 111- Brain’

Reserved digit codes: OIICS 3 continues to reserve terminating digits 0, 8 and 9 for ‘unspecified’, ‘multiple’, and ‘n.e.c’. codes, respectively.

    • *0 – Unspecified – ‘Other, unspecified’ codes have been removed. If you have enough information, to code it in an ‘Other’ group, it cannot also be unspecified.

    • *8 – Multiple – New selected multiple codes were added for Nature, Part of body, and Source/Secondary source to reduce lost information.

    • *9 - Not elsewhere classified (n.e.c.) - Removed selected n.e.c. codes where superseding codes are logically exhaustive

Aligning Codes with Data User Priorities

Other changes to the OIICS system were designed to capture information that is useful and relevant to targeting safety and health interventions. New codes were added to reflect changing technologies or emerging areas of interest.

Two coding structures were added to OIICS capture Worker Activity and Location. These structures were previously coded for the BLS Census of Fatal Occupational Injuries (CFOI) data, but they were not considered to be part of the OIICS coding system. These structures have been revised to compliment the rest of the OIICS system in order to create a more complete record of each incident.

Part of the value of OIICS is the continuity of surveillance series, particularly of the Event and exposure series. Care was taken to make only minimal changes to Event 1- and 2-digit series and to ensure that definitions within these series remained consistent to the extent possible.

Details of changes can be found below.

  1. Nature of injury or illness

  2. Part of body

  3. Event or exposure

  4. Source/Secondary source

  5. Worker Activity and Location

Nature of Injury or Illness

In general, this revision attempted to remove concepts of ‘Source’ and ‘Exposure’ from ‘Nature’ in order to simplify the structure. This led to the consolidation of traumatic versus non-traumatic versions of the same Nature outcome where possible. This concept is instead captured in Event. This change affected the following Nature codes:

  • Hernias

  • Disc disorders

  • Carpal and tarsal tunnel

  • Pinched Nerve

  • Allergic versus irritant bodily reactions

  • Blindness/deafness/tinnitus

Further changes to Nature are listed below in order of numeric code order.


Division 1 underwent a substantial reorganization. Most of the changes were at the 2-digit level, however, terminal codes have largely remained consistent.

    • NEW Group 10 - Traumatic injuries or exposures-- nonspecific and unspecified

      • Combined OIICS 2.01 concepts of 197* ‘Nonspecified injuries and disorders’ and 10- ‘Traumatic injuries and disorders, unspecified’

Major Groups 11-17 are organized according to:

    A) Injuries resulting from Mechanical Trauma
    • Group 11- Injuries to brain, spinal cord

    • Group 12- Severe wounds and internal injuries

    • Group 13- Surface and flesh wounds

      • NEW codes added for injuries specific to eyes and ears
    • Group 14- Soft Tissue Injuries

    B) Injuries resulting from Traumatic Exposure

    • Group 15- Burns, corrosions, electrical injuries

    • Group 16- Effects of poison, toxic, or allergenic exposure

    • Group 17- Effects of environmental conditions and exposures

    • Group 18- Multiple traumatic injuries and disorders
      • Codes expanded to reduce loss of detail in 'Multiple injuries n.e.c.' category


    • Group 24- Influenza and other respiratory infections moved to Division 3, ‘Infectious Diseases’

    • Group 27- ‘Musculoskeletal disorders’

      • Moved carpal/tarsal tunnel and Raynaud’s syndrome to 27* to be consistent with OSHA list of MSD

      • Reorganized group to include codes for radiculopathies


    Traumatic injuries of the musculoskeletal system (Nature 14*, excluding event 7*).

    Injuries causing acute disruption of soft tissues, resulting from a single incident of trauma, such as a car accident


    Acute overexertion Injuries resulting from a single incident (Nature 14*; Event 71*, 73*)

    Injuries resulting from a single incident of strain or overexertion


    Repetitive strain injuries (Nature 14* or 27*; Event 72*)

    Injuries result from prolonged or repetitive exposure lasting more than a single shift but are of a relatively minor nature, and without a medical diagnosis as a disorder.


    Diseases and disorders of the musculoskeletal system (Nature 27*)

    These conditions typically result from work activities that involve prolonged exposure to repetitive tasks, exertion of force, or maintenance of awkward postures. They may also be sequelae of a traumatic injury (Division 27*).



      • Group 32- Viral diseases

          • Added detailed codes for emerging diseases to correspond with ICD-10 codes

            1. i.e., Corona viruses and ‘Post-COVID conditions’ (e.g., Long COVID), Zika, East Equine Encephalitis, Ebola, etc.

          • Reorganized virus codes based on clinical presentation


      • No changes



      • Minimal changes



      • Minimal changes



      • Added combination codes for PTSD and traumatic injuries

    Part of Body

    Revisions to the Part of body structure were minor. The greatest change to this structure is that the updated rules of selection now allow for selection of internal part of body in conjunction with traumatic internal injuries. For example: if a person inhales hot gases and incurs thermal burns to lungs, the coder may now select ‘Part – Lungs’, rather than coding to the external part of body (i.e., chest). This results in more accurate data.

    • Internal organs of the trunk have been reorganized to group by body systems where possible to give more information about the specific system affected

    • Prosthetics are now coded with the part of body where the prosthetic is located to consolidate all injury types to a given region of the body and give more information about the location/ use of the prosthetic

      • Example: A damaged breast implant would now be coded to Part = breast(s). The concept of damage to prosthetics is captured in Nature

    Event or Exposure

    Rules of Selection

    While there are some significant changes to the ‘Event or exposure’ structure, a major goal of the revision was to maintain the Event series as much as possible at the 1- and 2-digit hierarchical levels. Only two major groups, ‘Injuries by other person, unintentional or intent unknown’ and ‘Injuries involving animals’, were reorganized from Division 1 (previously ‘Violence and other Injuries by persons or animals’ to a Division 6 – ‘Contact’. OIICS version 3.0 also reaffirms the order of precedence as the primary method for determining which event code to use when more than one code is applicable.


      • Moved injuries by animals to contact so that the division now includes only intentional acts of human violence

      • Expanded codes for ‘Hitting kicking, beating’ to better capture context

      • Added code for ‘Witnessing a violent act’



      • Added codes for ski incidents to ‘non-motorized vehicle incident’ group

      • Added more detailed codes for incidents occurring onboard vehicles in transport

      • Oil rigs will no longer uniformly be considered water vessels to allow flexibility for capturing the varied incidents involving this type of equipment



      • Moved ‘Explosions’ before ‘Fires’ in order of precedence

        • Previously an explosion that began as a fire would be coded as a fire only and the explosion would be missed, even if it was the more serious incident

      • Added explicit ‘Wildfires’ code



      • Moved ‘falls to lower level’ before ‘falls on same level’ in order of precedence

      • Added new codes for combination incidents involving ‘Falls to lower level’ AND ‘Contact’ or ‘Exposure’. ‘Contact’ and ‘Exposure’ information was previously lost due to ‘Falls’ higher placement in the order of precedence

        • ‘Fall to lower level resulting from exposure or contact’

        • ‘Fall to lower level resulting in exposure or contact’

      • Consolidated height categories to reduce the amount of information lost to unspecified codes when more detailed height intervals were unknown

        • Fall, less than 6 feet

        • Fall, 6-30 feet

        • Fall, more than 30 feet

      • New code for ‘Fall, slip trip while transitioning levels’



      • New code for ‘Exposure to electric arc’

      • Consolidated needlestick injuries into one code



      • Substantial changes to order of precedence within division

      • Now includes ‘Contact with animals’ and ‘Contact with other person, nonviolent or intent unknown’, which were previously classified in Division 1, along with violent acts

      • Highlighted injuries resulting during normal machine operation versus during maintenance or malfunction



      • ‘Overexertion’ codes redefined based on worker activity since individual harmful motions (i.e., twisting, bending, etc.) were not typically identified in case narrative information

      • Many codes for prolonged versus single exposure were consolidated due to lack of information in source documents


    Source and Secondary Source

    In general, source and secondary source codes underwent a moderate level of revision. Several new codes were added to capture emerging technologies or safety issues. Divisions 1-8 kept their previous super-category designations and contain minor revisions to codes. Division 9 received a major revision to allow for the capture of any safety equipment or interventions that failed to protect in a harmful incident. These are based on OSHA’s hierarchy of controls. (See below for details.) Finally, there have been significant changes to rules of selection. The goal of Source continues to identify the person or item that most directly harmed the person. Secondary source now aims to consistently capture contributing factors, including failed safety interventions, environmental conditions, specific machine parts, or other factors that provide detail on why the incident occurred.  



      • Revised chemical codes to conform to Pipeline and Hazardous Materials Safety Administration (PHMSA/HAZMAT) definitions

        • Any substances with an official HAZMAT designation can be coded based on the information presented on their required Material Safety Data Sheets (MSDS)

      • Drug classifications were expanded based on Department of Justice (DOJ) drug scheduling and the Veteran’s Association National Drug File (VANDF) classifications



      • Minimal revisions

      • Added group for “Wheeled containers, material moving equipment” (previously in Vehicles)



      • Revised Agricultural equipment to better accommodate agricultural industry data users

      • Expanded drilling and extraction machinery to better accommodate oil and gas industry data users

      • Added new group 37 “Pressurizing, separating, and phase changing machinery”

      • Added new group 38 category for “Flying and orbiting machinery” to accommodate unmanned flying machines.

      • Moved office machinery to Division 7- Tools, equipment to combine with other similar items



      • Moved raw earth and mineral materials from Division 5 (previously “Persons, plants, animals, minerals”) and created new Group 41 for raw and semi-finished materials

      • Revised Building materials (group 42) to reflect new types of available materials and to create a framework of material form by substance for easier classification

      • Added new group 463 for “Machine hydraulics and pressurized components”

      • Added new group 465 for “Batteries and related equipment”

      • Expanded application of “Vehicle parts” to also allow for use in coding non-mobile machine parts

      • New detail codes for

        • Augers (machine part)

        • Solar panels

        • Fiber optic and internet cables



      • Relocated minerals to Division 4, ‘Parts and materials’

      • Added new detail codes to accommodate types of commonly seen injuries

        • Shellfish (fishing injuries)

        • Nuts and peanuts (nut allergies)

        • Parasites (intestinal worms, toxoplasmosis, etc.)

        • Animal remains

        • Human remains

      • Expanded “Bodily conditions of injured or ill worker” to include selected underlying medical issues for when a worker’s medical conditions were a contributing factor to a workplace injury



      • Reduced detail for building types due to infrequent use

        • Building type will be captured with the new Location field for CFOI, which typically has more available case detail

      • Simplified codes for ground surfaces

        • Combined with natural outdoor “structures” such as mountains, embankments, and ditches that also serve as surfaces



      • Combined powered versus non-powered tools into groups by function since the powered/nonpowered distinction is often unknown

      • Moved office machinery from division 3 and combined with Division 7 codes to create “Media, office, and business equipment”

      • Moved ‘Protective equipment’ to Division 9

      • Expanded ‘Fishing equipment’ to ‘Athletic and Outdoor equipment’

      • Aligned firearms and weapons with military classifications



      • Emergency use vehicles are grouped together

      • Regrouped roadway vehicles to more closely align with NHSTA/FARS classifications, which are more often based on weight class

      • Non-powered material moving equipment relocated to Division 2



    Division 9 was redesigned to capture incident contributing factors. The division framework starts with apparel and worn devices, closest to the worker, and moving outward to the workers immediate work environment (i.e., safety equipment protocols based on OSHA’s hierarchy of controls) and the broader environment (weather and climate conditions).

    • Group 91- Apparel, laundry, linens

    • Group 92- Personal Protective Equipment (PPE) (Relocated from Division 7)

      • Other protective equipment (Relocated from Division 7)

      • Respirators (Relocated from Division 7, expanded to include NIOSH respirator classifications)

    • Group 93- Safety controls and equipment— except PPE

      • Safety equipment, except worn (NEW)

      • Engineering controls (NEW)

      • Autonomous or robotic system failure (NEW)

      • Communicable disease safety protocols (NEW, to capture COVID or infectious disease protocols)

      • Hazard communication and signage

      • Safety practices, administrative controls

    • Group 94- Factors and conditions specific to vehicles, mobile equipment

    • Group 95- Environmental and elemental conditions (kept from OIICS 2.01)


    Worker Activity and Location

      • Revised from CFOI structure to compliment information coded in Occupation, Event, Source and Secondary source

      • Formatted as rest of OIICS fields with ‘Definitions’, ‘Includes’, ‘Excludes’, and ‘Coding interactions’

      • Now organized with an order of precedence to assist in code selection


    Last Modified Date: February 1, 2024