Health, Safety, Security and Environment

HSE Interview Questioners

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Workplace health and safety are both the moral and legal responsibilities of most employers. Whether you’re working in an office or in a manufacturing warehouse, any type of workplace has its share of hazards. It is important for employers to thoroughly assess and effectively address each issue. This means performing a job safety analysis, providing education and training for your employees, supply appropriate PPE at no cost to the worker, removing or controls hazards, and cultivating a culture of safety.

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If you are planning to attend the HSE interview, followings are samples of the questions and answers will help you to understand the basic of HSE.

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Q. What is the Safety?

Safety is freedom from the unacceptable risk of harm. (The word safety drives from the Latin word „SALVUS‟ means uninjured and healthy)

Q.What are the responsibilities of an HSE Officer?
  • The HSE Officer acts an advisory capacity to the management and supervision with regards Health and Safety Environment,
  • He is to monitor and ensure that the activities are being performed with acceptable safety norms.
  • Helping supervisors to identify the hazardous and unsafe conditions and ensuring rectifications.
  • Conducting tool box meeting, Supervisors safety meeting, conducting training in various topics, conducting safety incentive program, conducting safety auditing/inspection.
  • Taking disciplinary action against the violations.
  • Conducting risk assessment and JSA, pre task meeting and all other project related safety requirements.
  • Keep track record all incidents at site.
  • He is to investigate hazards and dangerous occurrences, examine the cause of accident, carry out safety inspection on site and what remedial steps/action has been under taken.

( Read more about 68 HSE interview-questions/ )

Q.What is a ‘Permit to Work’ Procedure / Work Permit System?
  • The „Permit to Work‟ (PTW) Procedure is a formal written system, which utilize a document to control the work by means of potential hazards identification and risk assessment.
  • The work permit is also a means of communication among various supervisors or their respective belonging to operation, maintenance, controlling teams, and contract personnel, who are involved in work preparation and/or its execution.
Q.Explain Types of Work permits normally used in the oil & gas industry?

Types of Work permits: 5 types of work permit

  1. Hot Work Permit   (red)
  2. Cold Work Permit (green)
  3. Radiography Permit (yellow)
  4. Vehicle/mobile plant entry work permit
  5. Confined Space Entry Permit
(a)  Cold Work Permit:

A document that specifies precautions identifies hazards and controls all work that is not hot and radiographic in nature.

(b)   Hot Work Permit:

A document that specifies precautions, identifies hazards and controls all work involving actual naked flames, sparks or has potential for creating sparks or heat.

(c)  Radiography Work Permit:

A document that specifies precautions identifies hazards and control all work involving radiographic in nature.

(d)   Vehicle / Mobile Plant Entry Permit:

A document that specifies precautions identifies hazards and controls all work involving entry of a vehicle or mobile plant into a hazardous area.

(e)  Confined Space Entry Permit:

A document that specifies precautions identifies hazards and controls all work involving entry to an enclosure, which has limited means of entry or exit, not designed for continuous occupancy.

Q.Explain Each Work Permit Validity? (as per KOC)
Hot / Cold / Radiography Permit:

Valid for a maximum duration of seven consecutive days from the date of issue subject to renewal by the permit issuer.

Note: Validity Period for Cold or Hot work permit in Non-Hazardous area can be extended for a maximum one month with approval from concerned Team Leader.

Confined Space Entry Permit:

Valid for one continuous work shift or part thereof; however the permit is to be renewed / re-endorsed in case of crew change, transfer of responsibility, work suspension or as recorded in the permit.

Vehicle / Mobile Plant Entry Permit:

Valid for one continuous works shift for Vehicle entry, whereas for Mobile Plant Entry it is valid for maximum 7 consecutive working days from the date of issue subject to renewal by Permit Issuer.

Q.Explain Each Work Permit Distribution? (as per KOC)

Work Permit will be made out in FOUR COMPIES

  • The Original for worksite
  • 1st copy for Permit Applicant
  • 2nd copy of all permits (except cold work permit) forwarded to FIRE TEAM by the permit issuer
  • 3rd copy shall be retained by the issuing authority

Note: After completion of work and permit closure as per procedure…

Original kept on record with Permit Issuer. 1st copy shall be retained by the Permit Applicant (for minimum 6 months). 3rd copy can be given to Worksite Supervisor for their record.

Q.What is e-WP (Electronic Work Permit)? (as per KOC)

Electronic Work Permit (e-WP) is a web-based solution through KOC intranet to manage electronically the authorization process of non-routine activities which are carried out in KOC business as per Permit to Work Procedure (KOC.SA.004).

Q.What important details a work permit give?

It is a form, which is signed by higher responsible people to carry out the specific job. It clearly states:

  • What is to be done,
  • Where,
  • When and
  • What are the safety precautions to be taken?
Q.What is Cold work, Hot Work, and Radiography work?
Cold Work:

Any work that does not involve a source of ignition or naked flame or does not have spark generating potential is classified as a Cold Work.

Hot Work:

Any work which involves the use of naked or a source of ignition or spark generating potential is classified as a Hot Work.

Radiography Work:

Any work that involves the use of a radioactive source, shall be covered by a radiography work.

Q.What is the Excavation? And types of excavation?

Any man-made cavity, cut, trench or depression on an earth surface formed by earth removal.

Types of Excavation:
  1. Manual Excavation: The excavation without using any powered equipment.
  2. Mechanical Excavation: The excavation work using any electrical or mechanical equipment.
Q.Explain about Excavation Notification?

Excavation notification is a document to notify concerned authorities, who have responsibility and jurisdiction for safety and integrity of above ground and underground services existing at the propose site of excavation.

  • Excavation notification must be supported by a work permit.
    • Excavation notification is valid for 90 days from the date of issued.
    • Excavation notification is required for all excavations regardless of depth.
Q.Why is Excavation Notification required for excavation?

Excavation notification gives detailed information about the underground facilities, and it is to be signed by all KOC concerned departments to confirm that the proposed excavation location has been identified and all safety measures have been taken for the existing underground facilities.

  • Cave in or collapse of soil
  • Risk due to presence of underground installations, pipelines, cables.
  • Drowning due to water seepage into trench.
  • Soil vibration due to machinery / heavy vehicles operations in the vicinity.
  • Lack of Oxygen or asphyxiation etc.
  • Underground obstruction or damage to buried pipelines & services
  • Accidental fall of personnel or equipment inside a trench
  • Struck / hit by excavating machinery
  • Dropped / falling objects
  • Flammable & / or toxic gas release
  • Exposed to airborne contaminants
  • Fire & explosion
  • Electrical shock due to contact with energized electrical / telecom cable.
  • Possible presence of explosive devices
  • Damage to shallow underground services due to weight of heavy equipment such as mechanical excavator.
  • Encountering wet soil (mixed with water) or reaching water table.
  • Encountering contaminated soil
Q. Enlist precautions to be taken prior to being taken to and during excavation work?


What is the safety precautions required for a safe excavation?
  • No excavation work in KOC area without clearance of Explosive Ordinance Disposal (EOD).
  • No mechanical excavation closer than 5 meters to any hydrocarbon carrying pipeline.
  • No mechanical excavation closer than 3 meter to a non-hydrocarbon carrying pipeline, cables and services.
  • For any excavation deeper than 1m, ladder must be positioned projecting minimum 1 meter above the edge of the excavations.
  • Ladders shall be provided every 7.5 meters (25 feet) of lateral travel in the trench.
  • Ladders shall be securely supported at the bottom as well as at the top.
  • Excavated material shall be placed 1m from the edge of the excavation for depth up to 1.2 meter.

(Accordingly placement of excavated material shall be increased proportion to the depth of excavation.)

  • Heavy equipment, machinery shall be kept at least 3 meters away from the edge.
  • Any walkway across trench shall have scaffold type platform with handrails.
  • All trenches shall have barrier (such as fixed guardrails) and reflective warning notices clearly displayed. Flashing lights are mandatory during poor visibility.
  • The access to plant, equipment and emergency services must not be obstructed by the trenches.
  • No mechanical excavation is allowed inside the existing KOC facilities (Gathering Center, Booster Station, water injection and handling facilities, etc.)

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Q.What is confined space?
  • Any enclosure having a limited means of entry & exit and it is not designed for continuous occupancy.
  • There will be a presence of any hazardous substances such as flammable and toxic gases, oxygen deficiency, hot or humid atmosphere or any combination of it.

Examples: Process vessels, Tanks, Bins, Stacks, Large pipe, Duct, Pits & Trench etc. Any excavation with depth more than 1.2 meter.

Q.What are the Confined Space Hazards?

A confined space may have one or a combination of the following hazards:

  • Oxygen deficiency
  • Presence of flammable, combustible or pyrophoric materials (HC, Sludge etc.)
  • Presence of toxic gases, corrosive or hazardous materials (H2S, Co, NH3 etc.)
  • Poor illumination, Ventilation & Communication.
  • High temperature and humidity.
  • Limited entry & exit / Restricted access.
  • Restricted movement inside.
  • Falling / Tripping hazards
  • Presence of reactive or self-igniting material.
  • Hazard due to electricity or moving machinery.
  • Hazard due to pressurized fluid.
  • Hazard due to nature of work carried out inside confined space.
Q.What is the procedure for entering a confined space hazards?


What are the important PRECAUTIONS for confined space?
Procedure for entering confined space:
  1. Permit must be procured form operations, making sure of the following.
  2. Complete isolation of the space to be entered.
  3. Draining, depressurization and purging or cleaning should be performed.
  4. Gas test should be conducted to ensure no hazardous atmosphere is present.
  5. Space ventilation.
  6. A Pre task meeting must be conducted with all authorized entrants prior to entering the confined space.
  • The attendant (Stand by man) shall be assigned at the entrance to maintain communication with employees working inside to ensure their safety. A log book shall be maintained at the entrance to keep track of the people inside the space.
  • Safety attendant must be trained and authorized to use gas testing equipment.
  • Entrants must wear body harness, and if necessary a life line be attached to the harness to avoid entry-rescue.
  • Lighting should be provided, if necessary a maximum of 24 volts, lighting should be used attached a GFCI.
  • Only intrinsically safe or explosion-proof equipment shall be used inside.
  • Depending on the situation, emergency rescue team may be put on standby.
  • If an emergency occurs within the confined space, the standby person must not enter it until rescue team arrived.
  • Barricade the area with warning sign board.
Q.What you know about working in a confined space entry? OR Explain about confined space entry?

Any enclosure having a limited means of entry & exit and it is not designed for continuous employee occupancy.

  • Before entering in the confined space, must need to obtained a confined space entry work permit, make sure that all required isolation being done.
  • Frequently gas test is to be carried out to confirm that area is free of toxic gas or flammable atmosphere.
  • If the area is contaminated or it has oxygen deficiency the provided BA sets or air line respiratory system.
  • Conduct pre-task meeting for the employees who will be entering inside the confined area and get there signature to conform that they are aware of the hazards and safety measures.
  • The attendant (Stand by man) to assigned at the entrance. A log book shall be maintained at the entrance to keep track of the people inside the space. The attendant shall not be assigned to other duties. If an emergency occurs within the confined space, the standby person must not enter it until rescue team arrived.
  • The entering people should use body harness with lifeline for the emergency rescue purpose.
  • Any required electrical lighting or tools should not exceed more than 24 volts and attached with GFCI / ELCB. It should be intrinsically safe or explosive proof.
  • Barricade the area with warning sign board.
Q.Explain H2S? OR What is H2S and its characteristics explain?
  • H2S is produced or generated by decomposition of organic materials.
  • It is a highly toxic gas and highly flammable.
  • Its smell like rotten egg at low concentrations and not detectable by order at high concentration.
  • It is highly flammable. (flammable at 4.3% to 45.5% by volume in air)
  • It is colourless.
  • It is heavier than Air.(1.19)
  • It is highly soluble in water and other liquid.
  • When burned or flared it forms sulpher dioxide (SO2) which is also colorless and highly toxic gas.
  • The exposure limits 10 PPM is the maximum allowed for 8 hours.
  • Increasing exposure will cause headache and irritation of eyes.
  • 800 PPM or more will be instantly fatal.
Exposure Limit:

TLV-TWA of H2S      =          10 ppm

TLV-STEL of H2S    =          15 ppm

IDLH of H2S              =          100 ppm

Note: – Up to 10ppm work can be done without respiratory protection system.

  • 10 to 100ppm work can be done by SCBA or Air lined breathing apparatus.
  • Above 100ppm work not permitted, allowed only for rescue.
Q. What are prominent H2S HAZARDS?
H2S Hazards:
  • Eyes and respiratory irritation.
·       Dizziness, headache, nausea, abdominal pain.
  • Loss of consciousness, Brain damage possible, death / fatal.
Q. Explain the precautionary measures to be taken while approaching H2S prone area?
Precautionary Measures – H2S:
  • Sufficient number of escape masks shall be kept in areas where H2S is liable to present.
  • Incase H2S presence is suspected in an area, the persons must put on escape mask immediately and toxic gas test must be made immediately with appropriate detector to determined the concentration of H2S in air.
  • Working person should be equipped with personal detectors and alarming device to alert in case of H2S presence.
  • Incase of H2S alarm, all personnel should vacate the area after donning the escape set / breathing apparatus and report to the designated assembly point for mustering.
  • If working in H2S contaminated atmosphere must wear suitable BA set and work in pairs to support and rescue each other in the event of difficulties.
  • Know the wind direction and evacuate in the cross wind direction incase of H2S leak.
  • Never go to a low-lying area during H2S leak.
  • Paste H2S warning sign in H2S prone areas.
  • The presence or suspected of H2S in any part of the plant or sewer shall be reported immediately to supervisor and respective area fire station for arranging rescue and support.
Q.How to treatment of persons affected by H2S?

Positive pressure breathing apparatus must be worn by any persons attempting a rescue.

  • The victim must be immediately moved to fresh air, possibly in the upwind direction of the gas leak. The rescuer must be outside the contaminated area before removing his/her personal BA set.
  • If the victim has stopped breathing, resuscitation must be started immediately, using artificial respiration or a resuscitator if available. Resuscitation must be continued until the victim starts breathing unaided or until qualified medical assistance arrives. Medical help must be summoned as soon as possible.
Q.Define TLV-TWA, STEL and IDLH?

Time Weighted Average (TWA) concentrate of the contaminant in air over the normal work shift of 8 hours, to which workers can be exposed without respiratory protection in a 40 hour workweek.


Short Term Exposure Limit (STEL) when exposed only for a short period of 15 minutes. This maximum concentration can be allowed to breathe 4 times during 8 hours with minimum 1-hour interval between exposures.


Minimum concentration of contaminant in air which is Immediately Dangerous to Life and Health (Note: Air supplied respirators are required in IDLH atmospheres.)

Explosive range (TLV, STEL & IDLH) for different GAS:

Hydrogen Sulphide (H2S) 10 15 100
Sulphur Dioxide (SO2) 2 5 100
Ammonia (NH3) 25 35 300
Chlorine (Cl2) 0.5 1 10
Carbon Monoxide (CO) 25 50 1200
Acetylene (C2H2)      
Q.What is Flash Point (FP)?

The minimum temperature at which a flammable mixture of gas or vapor in air will momentarily flash when a source of ignition (spark) is introduced.

Q.What is Auto-Ignition Temperature (AIT)?

The minimum temperature required to initiate self-sustained combustion of a solid, liquid or gas in the absence of a source of ignition.

Q. What are LEL/LFL and UEL/UFL?
Lower Explosive Limit (LEL): or (Lower Flammable Limit)

Minimum concentration of vapor or gas in air which will burn when a source of ignition (spark) is introduced.

Upper Explosive Limit (UEL): or (Upper Flammable Limit)

Maximum vapor/gas to air concentration above which flame propagation will not occur,

i.e. the mixture is “too rich” to burn.

Note-1: Flammable Gas Detectors (Meters) measure % LEL, hence actual LEL means 100% of full-scale reading of the meter. Below LEL (100% of meter reading), a mixture is “too lean” to burn.

Note-2: LEL of airborne combustible dust: If the dust obscures vision at a distance of 5 feet (1.52 m) or less it is considered as at LEL (ex. Sulfur or coke).

Explosive range (Lower & Upper) for different GAS:

Flammable GAS LEL / LFL (by volume in air) UEL / UFL (by volume in air) AIT (by volume in air)
Hydrogen Sulphide (H2S) 4.5 % 45.5% 260 C / 500F
Sulphur Dioxide (SO2)      
Ammonia (NH3) 15 % 28% 651.57 C / 1204 F
Chlorine (Cl2)      
Carbon Monoxide (CO)      
Acetylene (C2H2) 2.5% 80%  
Methane-CH4 (Natural Gas) 5% 15%  
Petrol (Gasoline) 1.4% 7.6%  
Q.What is scaffolding?

Scaffolding is a temporary working platform to provide supports both men and materials for working place. It is used in maintenance, construction and demolition work etc.

Types of scaffoldings:-

  • Permanent scaffolding
  • Hanging scaffolding
  • Suspended scaffolding
  • Mobil scaffolding.
Q.What are the points to be checked while green tagging erected scaffolding?

Before using of scaffold check the tag (7 days validity).

Green tag we can use the scaffold and Red tag for not use and Yellow tag use only for scaffolding works.

  • Level and firmness of the ground.
  • Sole plate
  • Base plate
  • Standards
  • Ledger
  • Transom
  • Couplers
  • Planks (boards)
  • Toe boards
  • Braising
  • Guard rails
  • Mid rail
  • Out riggers
  • Ladders

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