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Coding Selection Rules

The Occupational Injury and Illness Classification System (OIICS) has specific rules of selection for coding Nature, Part of Body Affected, Source of injury or illness, Secondary Source, and Event or Exposure. To correctly code injuries and illnesses and to understand OIICS coded data, it is important to understand the selection rules and orders of precedence. Note: the selection rules below are also available on the graphical code trees by clicking on the initial information symbol for each tree (Info toggle SELECTION RULES). Be aware that there were significant changes in selection rules for source and event in the redesigned OIICS version 2.

Nature of Injury or Illness

The nature of injury or illness identifies the principal physical characteristic(s) of the work related injury or illness

  • Name the injury or illness indicated on the source document. Example: For strained back, choose Strains.
  • When two or more injuries or illnesses are indicated, and one is a sequela, aftereffect, complication due to medical treatment, or re-injury, choose the initial injury or illness. Example: If a laceration became infected developing into septicemia, choose Cuts, lacerations.
  • When two or more injuries or illnesses are indicated and one is more severe than the other(s) and is not a sequela or complication of the other injury or illness, select the more severe injury or illness Example: For sprained finger and fractured wrist, choose Fractures.
    • When a single event or exposure produces an injury and transmits a disease simultaneously, and one is more severe than the other(s), select the more severe injury or disease. Example: If a needlestick produces a puncture wound and transmits serum hepatitis, choose Type B viral hepatitis (serum hepatitis)
  • When two or more injuries or illnesses are indicated but neither of which can be determined as being more severe than the others, select the appropriate multiple injuries or illnesses classification code. Example: For fractured and severely burned left leg, choose Fractures and burns

Part of Body Affected

The part of body affected identifies the part of the body directly affected by the previously identified nature of injury or illness.

  • When the previously named injury or illness involves a single part, choose that part. Example: For fractured jaw, choose Jaw/chin.
  • Traumatic Injuries and Disorders including internal burns and are generally coded to the external part or location, including specific locations for the mouth and back. Example: For lumbar sprain, choose Lumbar region of the back. Exceptions are noted below.
    • When Intracranial Injury is identified, choose Brain.
    • When the injury or illness affects an entire body system, rather than a particular part, name Body Systems. Example: for hypothermia, choose Body Systems.
  • Internal body parts should be named when a disease, disorder, or condition originated at, or is limited to, that internal part. Example: for hepatitis, choose Liver.
    • When the illness is cancer, choose the classification code for the original site of cancer. Example: for lung cancer, choose Lung(s)
  • When the injury is an amputation, choose the classification code that represents the nearest part of body lost. Example: for amputation at knee, choose Lower leg(s).
  • When the previously named injury or illness involves two or more parts within the same division, select the multiple classification code that includes those parts. Example: If lower leg, foot, and ankle are burned, choose Multiple lower extremities locations, n.e.c.
  • When the previously named injury or illness involves parts from two or more divisions, select a code in Multiple Body Parts. Example: For injuries to arms and knees, choose Upper and lower limb(s). When the nature of injury is burns and smoke inhalation, select part of body code 899, Multiple body parts, n.e.c.

Source and Secondary Source of Injury or Illness

The Source and Secondary Source identify the objects, substances, equipment, and other factors that were responsible for the injury or illness incurred by the worker or that precipitated the event or exposure. The Source and Secondary Source are coded according to the previously identified Event or Exposure as dictated by the Rules of Selection.

General rules of selection for Source

  • Whole versus part
    • Part of a machine, tool, or vehicle

      If the injury or illness was inflicted by a specific part of a machine, tool, or vehicle, name the whole machine, tool, or vehicle as the source of injury except when:

      • the part separated from or was independent of the "whole";
      • the event is overexertion involving an outside source;
      • the injury was inflicted by an overhead powerline or the electrical cord of an appliance, tool, or machine;
      • the injury was inflicted by the floor of a vehicle in a non-transportation incident;
      • the injury was inflicted by a separate machine attached to a vehicle, such as a conveyor attached to a truck;
      • the incident involved a tractor and agricultural equipment combination.

      In those instances, code that part as source.

      Items being transported by a vehicle are considered part of the vehicle. For example, if a box that is being moved by a forklift strikes a worker while still on the forklift, the forklift is considered the source.

    • Part of a structure

      If the injury or illness was inflicted by a specific part of a structure (window, door, stairs) name that part as the source of injury.

  • Containers

    When an injury or illness was produced by a filled container, name the container, not the contents, as the source unless the injury or illness was directly inflicted by the contents, such as hot liquids or chemicals.

  • Bodily motion or position

    Name Bodily motion or position as the source of injury or illness only when the injury resulted solely from the stress or strain induced by the free movement of the body or its parts (voluntary or involuntary), or from the assumption of a strained or unnatural body position.

    Bodily motion or position includes injuries or illnesses resulting from reaching, turning, twisting, bending, walking, climbing, running, and from efforts to recover from a loss of equilibrium, provided that the loss of equilibrium does not result in a fall or in forcible contact with an object above the working surface.

    Do not name Bodily motion or position as the source of injury or illness if the injury or illness resulted from any of the following:

    • falling,
    • bumping into or striking an external object,
    • nonrepetitive lifting, pushing, pulling, wielding, or throwing an external object.

    For injuries or illnesses in which either Repetitive motion or Sustained viewing is coded as the event, select bodily motion or position as the source of injury or illness.

  • Choosing between multiple objects or substances:
    • When an injury results from forcible contact with two or more objects, either simultaneously or in rapid sequence, and it is impossible to determine which object directly produced the injury, select the source as follows:

      • When the choice is between a moving object and a stationary object, select the moving object. Example: If a person is struck by a rolling vehicle and thrown against a post, name the vehicle as the source of injury.
      • When the choice is between two moving objects or between two stationary objects, select that which was contacted last. Example: If a worker is struck by a roll of paper and then a box and it is unclear which caused the head injury, code the box as the source.

    • When an injury or illness results from two or more different objects or substances, all of which contributed to producing the injury or illness, select the source code as follows: the source code as follows:

      • Select the “Multiple” code for that combination of objects and substances if one exists at the appropriate level;
      •  When the two objects or substances are in the same division and there is no appropriate “Multiple” code, select the divisional n.e.c. code for that division. If they are in the same group within a division, select the group n.e.c.;
      • When the two objects or substances are not in the same division, use the code for Other sources, n.e.c.

  • Weather, atmospheric conditions, and geological events

    Select Weather and atmospheric conditions or geological events—Floods, Earthquakes, Avalanches—as the source of injury or illness when that is the only possible source identified.

    For example, if a worker sustained multiple injuries in an earthquake, and no other source could be determined, select earthquake as the source of injury. However, if an employee were driving in a rainstorm and was injured in an automobile accident, select the vehicle as the source.

General rules of selection for Secondary Source

  • Codes to be used

    Use the Source of Injury or Illness Classification Structure for coding secondary source of injury or illness.

  • When two objects or substances contributed to an event

    In the absence of a specific rule above, if two objects or substances contributed to an event, name the object, or substance which was not selected as the source. If more than two objects or substances, other than source, are involved, select:

    • powered or energized objects over nonpowered objects,
    • moving objects over nonpowered objects,
    •  objects actively contributing to the event over passive objects .

  • Weather, atmospheric conditions, and geological events

    Select Weather and atmospheric conditions or geological events - Floods, Earthquakes, Avalanches - as the secondary source of injury or illness when that is the only possible secondary source identified.

    For example, if a worker sustained multiple injuries when struck by an object in an earthquake, select earthquake as the secondary source.

  • No contributing factors

    If no object, substance, or person is determined to meet the definition and rules listed above, no secondary source is selected. Objects which inflict an injury, but which neither generated the source nor contributed to the event, should not be selected as the secondary source.

    For example, if a worker falls from a vehicle in a transportation incident and is injured when hitting the road surface, the road is not selected as the secondary source.

Rules of selection based on Event or Exposure

  • Violence and other injuries by person or animal

    Source: Name the person or animal responsible for the injury or illness.

    Secondary source: Name the injury-producing weapon, object, or substance, if any.

    Example: If a robber shoots a store clerk in the leg with a handgun, the source would be robber and the secondary source would be the handgun.

  • Transportation incidents

    Source: Name the vehicle the worker was in or on at the time of the incident. If the worker was struck by a vehicle while on foot, name the vehicle which struck him or her.

    Secondary source: Name the object or vehicle with which the worker’s vehicle collided, if any. If no collision occurred, then name the contributing object or substance, such as ice, rain, etc. And if two objects were struck, code the object that most likely caused the injury.

    Example: If the worker was driving a semitrailer that collided with a passenger van, the source would be the semitrailer and the secondary source would be the passenger van.

    Example: If the worker was driving a tractor pulling a plow, fell from the tractor and was struck by the plow, the source would be the tractor and the secondary source would be the plow.

  • Fires and explosions

    Source: Name the burning substance or object or the item that exploded.

    Secondary source: Name the ignition source or contributing factor, if known.

    Example: If a firefighter was burned while extinguishing an electrical fire in a warehouse, the source would be warehouse, and the secondary source would be electrical wiring

  • Falls, slips, trips
    • Slips and trips without falls

      Source: Name bodily motion as the source.

      Secondary source: Name the object or substance that contributed to the slip or trip, if known.

      Example: If a worker trips over a box on the floor and suffers a sprain in recovering, bodily motion is the source and the box is the secondary source.

    • Falls on same level

      Source: Name the surface on or from which the worker fell.

      Secondary source: Name the object or substance, if any, that contributed to the worker’s fall.

      Example: If a worker slips on a patch of ice in the parking lot and falls breaking her wrist, the source will be the parking lot and the ice will be the secondary source.

    • Falls to lower level

      Source: Name the equipment or part of the structure (structural element) from or through which the worker fell.

      Secondary source: Name the object or substance, if any, that contributed to the worker’s fall.

      Example: If a worker fell to the ground after the roof truss on which he was standing gave way, the source would be the roof truss. The secondary source is left blank because no contributing factor other than the roof truss was mentioned.

  • Contact with objects and equipment

    Source: Name the object or substance that directly injured the worker.

    Secondary source: Name the object or substance, if any, that contributed to the contact.

    Example: If a worker is injured from a box falling from a forklift, the box is named as the source, and the forklift is selected as the secondary source.

  • Exposure to harmful substances or environments

    Source: Name the substance or environmental condition that injured the worker.

    Secondary source: Name the object or environment through which the worker was exposed.

    Example: If a worker suffers heat exhaustion while cleaning the interior of a tanker truck, heat would be named as the source and the tanker truck interior would be the secondary source.

    Example: For indirect contacts with electric current: If a worker is electrocuted from contacting a ladder touching a power line, code the ladder as the source, and the power line as the secondary source.

  • Overexertion and bodily reaction
    • Overexertion involving outside sources

      Source: Name the object over which the worker was exerting physical effort.

      Secondary source: Name any contributing object or substance, if any.

      Example: If a worker strains her back while lifting a box, code the box as the source. Leave secondary source blank since there was no contributing object or substance.

    • Repetitive motion and bodily reaction

      Source: Name bodily motion or position of the injured, ill worker.

      Secondary source: Name the contributing equipment, object, or substance, if any.

      Example: If a worker suffers tendonitis in the wrist from cutting meat all day, the source is bodily motion and the secondary source is the knife.

Event or Exposure

The event or exposure describes the manner in which the injury or illness was produced or inflicted by the source of injury or illness.

  • When the injury or illness occurred as a result of contact with or exposure to an object or substance, select the event or exposure which best describes the manner in which that contact or exposure occurred.
    • The event categories are listed in order of precedence, such that the categories are ordered as follows:
      • Violence and other injuries by persons or animals
      • Transportation incidents
      • Fires and explosions
      • Falls, slips, trips
      • Exposure to harmful substances or environments
      • Contact with objects or equipment
      • Overexertion and bodily reaction
      • Nonclassifiable
      When two or more of these events occurred, select the first event listed above.
    • In general, when two or more events occurred within the same subcategory, select the first event listed in the code sequence.
  • Injuries involving the normal worksite tasks and actions of the injured worker and co- workers are considered accidental by default unless information to the contrary is provided.
(Source: BLS OIICS Coding Manual, January 2012)
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