IICRC HST Exam Study Guide Questions With 100% Correct Answers | Graded A+ | 2026

IICRC HST Exam Study Guide Questions With 100% Correct Answers | Graded A+ | 2026 Industrial Hygiene - answer-Science and art devoted to the anticipation, recognition, evaluation, prevention, and control of those environmental factors or stresses arising in or from the workplace which may cause sickness,, impaired health and well being, or significant discomfort among workers or among citizens of the community. Occupational Health and Safety - answer-Same definition as "industrial hygiene" ; Science and art devoted to the anticipation, recognition, evaluation, prevention, and control of those environmental factors or stresses arising in or from the workplace which may cause sickness,, impaired health and well being, or significant discomfort among workers or among citizens of the community. Principles of health and safety hazard identification rely on these 3 basic criteria - answerRecognition - of a hazard or potential hazard Assessment - and eval of the hazard Controls - that are implemented to minimize hazard Hazard - answer-Any source or situation with a potential for harm in terms of a human injury or ill health, damage to property, damage to the workplace environment, or any combination of these. Risk - answer-It is the chance or probability that a person will be harmed or experience an adverse health effect if exposed to a hazard. May also apply to situations with property or equipment loss.What is the purpose of a hazard/risk assessment? - answer-to identify hazards and risks in the workplace so that workers are made aware of unsafe conditions at a worksite. Occupational Illness - answer-A health problem caused by exposure to health hazards in workplace Occupational injury - answer-Injury that results from a work-related accident or exposure involving a single incident in the work environment. Hazard-Contributing Factors: - answer-People Equipment Materials Environment Process Kinds of Hazards: - answer-Machine Energy Confined Space Material Handling Work practice/Ergonomic Chemical/Biological Aim of hazard/risk assessment process is to - answer-remove a hazard or reduce the level of risk by adding precautions or control measures as necessary. Levels of Risk involved with Hazard - answer-Very Low Low MediumMedium High Very High Hazard Level: Very Low - answer-Considered acceptable Hazard Level: Low - answer-No controls required unless can be implemented at low cost Hazard Level: Medium - answer-Consideration should be whether the risks can be lowered, where applicable, to a tolerable level and preferably to an acceptable level, but the cost of additional risk reduction measures should be taken into account Hazard Level: High - answer-Substantial efforts should be made to reduce the risk. Risk reduction measures should be implemented urgently within a defined period of time and it might be necessary to consider suspending or restricting the activity, or to apply interim risk control measures, until this has been completed. Arrangements should be made to ensure that controls are maintained, particularly if the risk levels are associated with extremely harmful consequences Hazard Level: Very High - answer-These risks are considered unacceptable. Substantial improvements in risk control measures are necessary so that the risk is reduced to a tolerable and acceptable level. The work activity should be halted until risk controls are implemented that reduces the risk so that it is no longer very high. If it is not possible to reduce the risk, the work should remain prohibited. Hierarchy of Controls - answer-Elimination/Substitution Engineering Controls Administrative Controls Work PracticePPE Engineering Control - answer-something that is a physical altercation that is built or implemented around the hazard minimizing the hazard making it safer. Placed at the source of the hazard. accident vs incident - answer-Accident - leaves someone hurt/dead or something is destroyed/damaged as a result of a occurrence Incident - The same occurrence but no one is hurt and nothing is damaged or destroyed. (near misses, close calls) Accident - answer-is an unexpected event that results in injury to persons, property damage or loss Incident (near miss) - answer-is an unexpected event that did not cause personal injury this time but had a potential of causing injury to persons or property damage 3 distinct phases of an accident/incident - answer-Initiatory phase - all events that lead up to the accident/incident. Can be a lengthy period of time of a short period of time Concluding phase - usually the time that the energy is released till it impacts (point of impact). Usually a short period of time Result phase - the time from impact to the time the energy has stopped flowing When investigating an accident, often the most overlooked thing is - answer-evaluating the scene closely before trying to take care of an injured workerProcess of Accident Investigation: - answer-Evaluate Scene Take care of injured worker(s) Report accident Preserve evidence Record evidence/take photos Gather facts Interview Gather physical evidence Written report Recommendations Follow up Examples of Physical Evidence: - answer-Positions of injured workers Equipment Materials Safety devices Position of guards and controls Damage to equipment Housekeeping Weather, lighting and noise conditions Sketches and photos Job Hazard Analysis (JHA) - answer-Beginning of safety inspection process. The procedure used to make a job safe by identifying hazards in each step of the job and developing measures to counteract those hazards. (First step in 2-step program that culminates in JSA) WATCHING FOR:People Hazards Equip Hazards Material Hazards Enviro Hazards Process Hazards 5 steps of Job Hazard Analysis (JHA) - answer-1. Select the job being analyzed 2. Break the job down into a sequence of tasks 3. Identifying of potential hazards in each task 4. Determining preventative measures to control these hazards 5. Communicating the information to others Benefits of Job Hazard Analysis (JHA) - answer-does not rely on individuals memory process prompts recognition of hazards More people involved, allows for wider base of experience and acceptance of the procedure May identify previously undetected hazards and increase job knowledge Safety and health awareness raised, communication improved, acceptance of safe work procedures is promotedHow are potential hazards identified? - answer-two common techniques: Kepner and Tregoe method - based on "Change Analysis" Gibson and Haddon approach - based on unwanted energy flow/barrier (Energy-barrier Approach) Change Analysis - answer-An analysis that projects the effects a given system change is likely to have on an existing system. Not done at a fixed workstation. Possibility of things changing is substantial. Parameters for Change Analysis - answer-A sensory signal: color, shape of object, emitted sound, odor, light level, position of handle, height of pedal A process specification: pressure, temperature, concentration, flow rate A dynamic component: motion, sequence, pace, speed change, friction A force or mass: electrical power, chemical energy, torque, impulse, impact A geometric value and time: location, dimensions, rate A piece of equipment: protective devices, position of a part, part in motion Environmental condition: weather, snow, rain, nuisanceEnergy Barrier Approach - answer-hazard is defined as uncontrolled energy flow and its possible contact with people and equipment. Ex. Electrical - Thermal - Moving belts and breaking belts - Kinetic motions - human and machine - Biological/chemical - Radiation - Noise - Stored energy Procedure for Energy Barrier Approach - answer-Identify the energy sources producing a risk. Describe the way the energy can come in contact with employees.