Department of the Interior, Risk Assessment System (RAS)

Department of the Interior Guidelines for Prioritizing and Correcting Health and Safety Deficiencies


These guidelines provide a Department wide Risk Assessment System (RAS) for prioritizing the correction of health and safety deficiencies.  The RAS provides managers with a methodology for identifying hazardous conditions that warrant immediate action and those that can be addressed in the future.

Risk Assessment System

The RAS ranks health and safety hazards using Risk Assessment Codes (RAC).  The RAC considers the hazard severity, the probability of occurrence, and the number of people exposed or the potential loss in the event of a failure. 

RAC Code Description
1 RAC-1 represents an immediate danger to life, health or property and requires emergency correction or hazard controlled to a lower level of risk as soon as possible within that work shift.
2 RAC-2 represents a high level of threat to life, health or property and requires hazard correction or hazard controlled to a lower level of risk as soon as possible, but no later than 15 days.
3 RAC-3 represents a medium level risk to life, health or property, with correction planned and completed, or hazard controlled to a lower level of risk within 12 months
4 RAC-4 represents a low level risk, with correction planned and completed, or hazard controlled to a lower level of risk within a 2-year period.
5 RAC-5 represents the lowest level risk and is considered minor.  The correction of these risks can be planned in the out-years of a five-year plan.
Severity Risk Assessment Code
Catastrophic (I) 1 1 2 3
Critical (II) 1 2 3 4
Significant (III) 2 3 4 5
Minor (IV) 3 4 5 5
Probability: Frequent (A) Likely (B) Occasional (C) Rarely (D)

Risk Assessment System Matrix

The SEVERITY CODE in the risk assessment system matrix describes the most serious type of injury or illness that can reasonably be expected from the exposure to the hazard.

Catastrophic Immediate and imminent danger of death or permanent disability, chronic or irreversible illness, major property or resource damage. I
Critical Permanent partial disability, temporary total disability greater than 3 months, significant property or resource damage II
Significant Hospitalized minor injury, reversible illness, period of disability 3 months or less, loss or restricted workday accident, compensable injury illness, minor property or resource damage III
Minor First aid or minor medical treatment.  Presents minimal threat to human safety and health, property or resources, but is still in violation of a standard. IV

The PROBABILITY CODE in the risk assessment system matrix describes the likelihood that a condition related hazard will occur. Relevant factors to consider include:

Frequent Immediate danger to health and safety of public, staff, or property and resources; occurs frequently or continuously. A
Likely Probably will occur in time if not corrected, or probably will occur once or more times during the life of the system. B
Occasional Possible to occur in time if not corrected. C
Rarely Unlikely to occur; May assume exposure will not occur. D

A higher Probability Code could be used if the hazard has the potential to expose a large number of individuals, the hazard is found throughout the facility, or the hazard can cause widespread interruption of normal operations.  A higher Probability Code should also be used when the frequency of exposure to the hazard, or duration of exposure, increases.

Separating employees or the public from the point of danger through the use of fencing, barricades, etc can reduce the probability code.  Hazard controls that do not require employee or public interactions are preferable to those that require user actions, and can also result in a lower probability code.


The Risk Assessment System provides management across the Department with full and accurate health and safety risk ranking information in order to make informed decisions concerning hazard control.  Using the RAS also provides decision-makers with a consistent and defensible approach to prioritizing health and safety hazard abatement efforts among the many competing resource demands and priorities.



U.S. Department of the Interior
Occupational Health and Safety Program - SafetyNet
1849 C Street, N.W., MS 5558-MIB • Washington, D.C. 20240
(202) 513-0767
..Last Updated on 08/13/08