150 Essential EHS Terms Explained Simply | EHSShala

Understanding EHS terminology is the first step for any professional working in environmental compliance, industrial safety, pollution control, or sustainability. This guide is written from real Indian industry experience - combining lessons from a father who worked since 1981 and a son who started seeing the field in 2007. These 150 essential EHS terms are explained in simple language with examples, mistakes, incidents and memory tricks, so beginners and working professionals can remember them for life.

Written by someone who grew up watching his father who was industry expert in this field since 1981, and later entered the industry himself in 2007 - first as a data analyst, then as a builder of environmental compliance automation.

If you're new to EHS, preparing for interviews, or brushing up your basics, this guide will feel like sitting with a senior who explains everything in simple language, with memory tricks, incidents, and real Indian examples.

This is not a boring dictionary.
This is EHS Shala – Explained by Experience.

Basics of EHS

Environment, Health and Safety (EHS) is a system used by industries to protect:

• workers

• nearby citizens

• air, water and land
  from harm caused by industrial activities.

In simple terms:

• Environment deals with pollution and waste

• Health deals with occupational exposure and illness

• Safety deals with accidents, injuries and fire risks

This section directly answers:

• What are the basics of EHS?

• What are the concepts of EHS?

Air Pollution Terms (15 Terms)

1. PM2.5 (Particulate Matter 2.5)

Simple meaning: Ultra-fine dust (2.5 microns) that directly enters your lungs and sometimes your bloodstream.
Where you see it: Ambient monitoring reports, AQI boards, NAAQS comparisons.
Common mistake: Thinking PM2.5 comes only from industry. In Indian cities, a large portion is from traffic and road dust.
Memory trick: “2.5 = 2½ problems: lungs + heart + headache.”
Industry Expert’s line: “PM2.5 doesn’t knock… it just enters.”

2. PM10 (Particulate Matter 10)

Meaning: Coarser dust that mostly sticks to your nose and throat area.
Where seen: Construction sites, cement plants, material handling.
Memory trick: 10 = ‘Tenants at the entrance’. They stay at the entry of your breathing system.

3. SO₂ (Sulphur Dioxide)

Source: Burning of coal, furnace oil, diesel.
Impact: Irritates throat, contributes to acid rain.
Common mistake: Confused with H₂S (rotten egg smell gas).
Memory trick: SO₂ = “Sore Throat Oxide.”

4. NOx (Oxides of Nitrogen)

Meaning: Mainly NO + NO₂ produced during high-temperature combustion.
Where present: DG sets, boilers, engines.
Best practice: Before blaming fuel quality, check burner tuning and air–fuel ratio.

5. HCl (Hydrogen Chloride)

Source: Pickling, chemical processes, incineration.
Common confusion: Mistaken as chlorine gas (Cl₂).
Memory trick: HCl = Hot Choking Line.

6. VOC (Volatile Organic Compounds)

Meaning: Chemicals that easily evaporate and pollute air.
Common places: Paint shops, printing, pharma, adhesives.
Practical sign: Eye irritation or strong smell in a closed room often means VOCs.

7. Ozone (O₃)

Fun fact: Good in stratosphere, bad near ground level.
Mistake: People think “ozone smell = clean air,” but high ozone actually irritates lungs.

8. AQI (Air Quality Index)

Meaning: A single number (0–500) that summarises overall air quality.
Memory trick: AQI = “Air Quality in One number.”
Where used: Cities, construction sites (mandatory in Mumbai).

9. NAAQS (National Ambient Air Quality Standards)

Meaning: India’s legal limits for ambient air pollutants.
Industry Expert’s tip: “Never read a monitoring report without NAAQS beside you.”

10. CAAQMS (Continuous Ambient Air Quality Monitoring Station)

Meaning: A fully automated station that continuously monitors ambient air.
Common confusion: CAAQMS = ambient; CEMS = stack emissions.
Memory trick: CAAQMS = City Air Always Quickly Measured Station.

11. CEMS (Continuous Emission Monitoring System)

Meaning: Instruments installed on stacks to measure emissions continuously.
Where used: Power plants, cement, steel, hazardous waste incinerators.
Important: Data often goes directly to SPCB servers.

12. Isokinetic Sampling

Meaning: Sampling flue gas at the same speed as the gas flow inside the duct.
Reason: Prevents under-sampling or over-sampling of particles.
Memory trick: ISO = SAME.
Incident: A junior once rushed the sampling and ruined a ₹40,000 monitoring test.

13. Bag Filter

Meaning: A device that traps dust using fabric bags.
Common issue: High differential pressure (DP) due to bag choking.
Industry Expert’s habit: He tapped the baghouse wall; a different sound meant choking.

14. ESP (Electrostatic Precipitator)

Meaning: Uses electric charge to attract and collect dust.
Where used: Power plants, large boilers.
Memory trick: ESP = Electricity + Smoke + Plates.

15. Scrubber

Meaning: Uses liquid to remove gases and sometimes dust from flue gas.
Types: Wet and dry scrubbers.
Common mistake: People assume “water is flowing so it’s working.”
Reality: Wrong pH or nozzle choking makes scrubber ineffective.

Water & Wastewater Terms (15 Terms)

16. BOD (Biochemical Oxygen Demand)

Meaning: Oxygen required by microorganisms to break down organic matter.
Why important: High BOD = high organic pollution.
Where used: ETP inlet/outlet, sewage treatment, environmental audits.
Memory trick: BOD = Bacteria’s Oxygen Demand.
Common mistake: Confusing BOD with COD during reporting.

17. COD (Chemical Oxygen Demand)

Meaning: Oxygen needed to chemically oxidise organic matter (both biodegradable and non-biodegradable).
Difference from BOD: COD is almost always higher.
Memory trick: COD = Complete Oxygen Demand (easy way to remember).

18. TSS (Total Suspended Solids)

Meaning: Particles suspended in water - silt, sludge, fibres.
Where seen: Clarifier performance, ETP outlet quality.
Common mistake: Confusing TSS (particles) with TDS (dissolved salts).

19. TDS (Total Dissolved Solids)

Meaning: Dissolved salts like chlorides, sulphates, minerals.
Importance: High TDS affects boilers, cooling towers, RO systems.
Memory trick: TDS = Tiny Dissolved Stuff.

20. pH

Meaning: Acidity or alkalinity of water (0–14 scale).
Best practice: pH between 6.5–8.5 for most treated effluent.
Mistake: pH meter calibration ignored for months.

21. Conductivity

Meaning: Ability of water to conduct electricity - linked to TDS.
Memory trick: More salts = more conductivity.
Where used: RO feed water, process water quality.

22. Oil & Grease (O&G)

Meaning: Oils, fats, petroleum residues in wastewater.
Where seen: Auto workshops, pharma, chemical units.
Best practice: Always check skimming tank performance.

23. MLSS (Mixed Liquor Suspended Solids)

Meaning: Concentration of biomass in aeration tank.
Importance: Controls biological treatment efficiency.
Memory trick: MLSS = Microbes’ Living Space & Strength.

24. MLVSS (Mixed Liquor Volatile Suspended Solids)

Meaning: Portion of MLSS that is actually alive (biomass).
Why important: Tells strength of active microbes.

25. DO (Dissolved Oxygen)

Meaning: Amount of oxygen dissolved in water.
Where used: Aeration tank performance.
Best practice: Maintain DO between 1.5 to 3 mg/L for efficient treatment.

26. Sludge Volume Index (SVI)

Meaning: Measures settling ability of sludge.
Memory trick: SVI = Sludge’s VIP quality - tells how well it will settle.
Problem: High SVI → bulking sludge → poor settling.

27. Clarifier

Meaning: Tank where solids settle and clear water flows out.
Mistake: Not checking scraper mechanism → sludge builds up.
Industry Expert’s note: “Clarifier se bachke koi paani nahi jaata - it shows everything.”

28. Equalization Tank (EQ Tank)

Meaning: Tank used to homogenize wastewater before treatment.
Why important: Prevents shock load on ETP.
Memory trick: EQ = Equal Quality of wastewater.

29. Aeration Tank

Meaning: Tank where bacteria degrade organic matter with oxygen.
Key parameter: MLSS, DO, air flow.
Mistake: Not measuring DO during peak load.

30. RO (Reverse Osmosis) Reject

Meaning: Concentrated wastewater stream from RO membrane.
Problem: Very high TDS.
Best practice: Separate line + proper disposal.

31. Treated Effluent

Meaning: Final outlet water after ETP/STP.
Important: Must comply with MPCB/CPCB norms.
Memory trick: This is the water everyone checks first during audits.

Hazardous Waste Terms (25 Terms)

32. Hazardous Waste (HW)

Meaning: Waste that can be harmful to humans or the environment due to toxicity, flammability, corrosion or reactivity.
Example: Spent solvents, paint sludge, used oil, ETP sludge.
Common mistake: Treating HW like normal wet/dry waste.
Memory trick: HW = Handle Wisely.

33. Schedule I Waste

Meaning: Specific hazardous waste streams listed by CPCB/MoEF.
Example: Spent acid, spent organic solvents.
Where used: Identifying reporting category for Form 3 or Form 4.

34. Schedule II Waste

Meaning: Waste having concentration of hazardous constituents above threshold limits.
Memory tip: Not about waste type - about hazardousness level.

35. Schedule III Waste

Meaning: Hazardous waste applicable for import/export.
Used in: Transboundary movement rules.
Memory trick: III = International Import/India.

36. Used Oil

Meaning: Any oil contaminated by impurities (lubricants, engine oil).
Common mix-up: People treat used oil as “normal waste oil”.
Rule: Must be stored in leak-proof containers + sold to authorized recyclers only.

37. Waste Oil

Meaning: Oil which is unsuitable for recycling or reuse.
Difference from used oil: Lower recycling value, more contamination.
Audit issue: Often mixed with used oil → attracts penalties.

38. E-Waste

Meaning: Electronic waste such as old computers, monitors, PCBs, batteries.
Best practice: Maintain vendor receipts + recycling certificates.
Memory trick: Anything with plug → E-waste.

39. Biomedical Waste (BMW)

Meaning: Waste from hospitals, clinics, labs.
Example: Needles, syringes, pathological waste.
Caution: Industries with medical rooms often forget BMW rules.

40. Manifest

Meaning: A document that tracks hazardous waste movement from generator → transporter → TSDF → disposal.
Industry Expert’s advice: “No hazardous waste movement without manifest = No safety.”

41. TSDF (Treatment, Storage & Disposal Facility)

Meaning: Authorized site where hazardous waste is treated and disposed.
Where used: Sending ETP sludge, contaminated materials, HW requiring landfill.

42. Landfill Waste

Meaning: Inert or treated hazardous waste suitable for landfill.
Mistake: Sending untreated sludge → illegal.

43. Incinerable Waste

Meaning: Waste that needs high-temperature destruction.
Examples: Pharma residues, solvents, high-organic sludge.
Memory trick: If it burns → it earns (incinerator).

44. Co-Processing

Meaning: Using hazardous waste as alternative fuel or raw material in cement kilns.
Advantage: Zero residue disposal.
Common in: Cement industries.

45. Form 3

Meaning: Hazardous waste inventory register to be maintained by industries.
Mistake: People only maintain it yearly - should be continuous.

46. Form 4

Meaning: Annual hazardous waste return submitted to SPCB.
Memory trick: Form 4 = ‘For Report’ (annual report).

47. Form 10

Meaning: Manifest form for hazardous waste movement.
Critical for: Traceability and legal compliance.

48. Labeling of Hazardous Waste

Meaning: Every HW storage container must have proper label:

• Name of waste
• Category
• Hazard symbols
• Handling precautions
  Mistake: Companies reuse labels → confusion during audits.

49. Storage Area

Meaning: Designated room/zone for HW with bund walls, roofing, and impermeable flooring.
Common violation: No spill kit or no fire extinguisher nearby.

50. Compatibility Chart

Meaning: Table showing which chemical waste can be stored together.
Example: Acids + alkalis = NO.
Life-saving tip: Never mix oxidizers and organic waste.

51. Leachate

Meaning: Contaminated liquid drained from waste.
Problem: Can contaminate soil and groundwater.
Memory trick: Leachate = Leakage Liquid.

52. MSDS / SDS (Material Safety Data Sheet)

Meaning: Safety document with hazard properties, PPE, first aid, storage guidelines.
Best practice: Keep SDS updated for all chemicals and waste streams.

OSHA – Occupational Safety and Health Administration

53. Spill Kit

Meaning: Emergency kit for chemical spill response.
Contains: Absorbents, pads, neutralizers, gloves.
Must be placed: Near HW storage, chemical handling areas.

54. Reactive Waste

Meaning: Waste that reacts violently with air, water or other chemicals.
Example: Sodium, peroxides.
Rule: Strictly separate storage.

55. Toxic Waste

Meaning: Waste harmful to human health due to high toxicity.
Testing: TCLP (Toxicity Characteristic Leaching Procedure) used to confirm.

56. Flammable Waste

Meaning: Waste which can catch fire easily (low flash point).
Examples: Solvents, paint residues.
Memory trick: “If smell is sharp and ignites fast → flammable.”

57. Corrosive Waste

Meaning: Waste that dissolves metals or burns skin (strong acids/alkalis).
Check: pH < 2 or pH > 12.5.
Best labels: Acid-proof, clear signage.

58. Oxidizing Waste

Meaning: Waste that supplies oxygen → increases fire risk.
Examples: Nitrates, peroxides.
Rule: Never store near flammable waste.

Industrial Safety Terms (25 Terms)

Core Safety Concepts (Very Important for Interviews & Audits)

• Hazard: Anything that can cause harm

• Risk: Chance of that hazard causing harm

• Risk Assessment: Identifying hazards, evaluating risk, and deciding controls

59. Hazard

Meaning: Any source with potential to cause harm (injury, illness, property damage).
Examples: Chemical, electrical, mechanical hazards.
Memory trick: Hazard = has ability to hurt.

60. Risk

Meaning: The chance that a hazard will actually cause harm.
Formula: Risk = Hazard × Exposure
Insight: High hazard + zero exposure = low risk.

61. Near Miss

Meaning: An incident that almost caused harm but didn’t.
Best practice: Treat near misses like “free warnings”.
Industry Expert’s line: “Near miss ignored becomes next accident.”

62. Incident

Meaning: An unplanned event that did not cause injury but disrupted normal operations.
Difference from near miss: Incident may involve property damage.

63. Accident

Meaning: An unplanned event that causes injury, illness, or damage.
Common mistake: Calling accidents “minor”. Every accident must be logged.

64. Unsafe Act

Meaning: A human action that increases the chance of accident.
Examples: Not wearing PPE, bypassing safety devices.
Truth: 80–90% of workplace accidents trace back to unsafe acts.

65. Unsafe Condition

Meaning: A physical or environmental condition that can cause harm.
Examples: Oil spills, broken guard, exposed wires.

66. Work Permit System

Meaning: Formal approval process before doing high-risk activities.
Types: Hot work, confined space, electrical, height work.
Best practice: No shortcut on permits - EVER.

67. Hot Work Permit

Meaning: Authorization for welding, cutting, grinding, or any spark-producing work.
Mandatory: Fire extinguisher + fire watch.

68. Confined Space

Meaning: A space with limited entry/exit, poor ventilation, and potential for hazardous atmosphere.
Examples: Tanks, pits, sewers.
Golden rule: No entry without gas test.

69. LOTO (Lockout/Tagout)

Meaning: Procedure to isolate energy sources before maintenance.
Memory trick: LOTO = Lock Once, Try Once.
Common mistake: Only tagging → no lock → high accident risk.

70. Work at Height

Meaning: Any work done above 1.8 meters (in India) where fall risk exists.
Essential: Full-body harness + anchorage.
Mistake: Rope tied to weak points.

71. Full Body Harness

Meaning: PPE used to prevent falls.
Insight: Inspect stitching, D-ring, buckles before use.

72. SCBA (Self-Contained Breathing Apparatus)

Meaning: Breathing device with its own air supply.
Used in: Gas leaks, confined space rescue.
Memory trick: SCBA = Safe Clean Breath Always.

73. MSDS / SDS (Material Safety Data Sheet)

Meaning: “Safety instruction manual” for any chemical.
Must check: Hazards, PPE, first aid, storage rules.
Mistake: Using outdated SDS.

74. Flash Point

Meaning: Lowest temperature at which a liquid gives off vapour that can ignite.
Lower flash point = higher fire risk.
Example: Petrol has very low flash point.

75. Fire Triangle

Meaning: Three things needed for fire - Fuel, Heat, Oxygen.
Tip: Remove just ONE → fire cannot exist.

76. Fire Extinguisher Types

Examples:

• Water
• Foam
• CO₂
• DCP
• Clean agent
  Memory trick: Use CO₂ for electrical fires. Never water.

77. Ergonomics

Meaning: Designing workplace to fit human body.
Examples: Chair height, monitor level, lifting posture.
Mistake: Considering ergonomics only for office staff. Workers need it more.

78. Machine Guarding

Meaning: Safety barriers that prevent contact with moving parts.
Common violation: Guards removed “for faster work”.

79. PPE (Personal Protective Equipment)

Meaning: Safety gear worn by workers - helmet, gloves, goggles, shoes, masks.
Hierarchy: PPE is the last line of defense, not first.

80. Safety Signages

Meaning: Visual warnings/instructions - mandatory, prohibition, hazard, directional.
Tip: Use multilingual signs in Indian factories.

Read more about Factories act 1948

81. Toolbox Talk (TBT)

Meaning: Short safety discussion before starting work.
Goal: Refresh safety awareness.
Best practice: Keep it practical, not lecture-style.

82. Emergency Assembly Point

Meaning: Safe zone where workers gather during emergencies.
Must have: Clear signage + headcount checklist.

83. First Aid Kit

Meaning: Basic medical supplies for initial treatment.
Mistake: Incomplete kit or expired medicines.

84. Accident Investigation

Meaning: Systematic analysis of why an accident happened.
Goal: Prevent recurrence, not assign blame.
Memory trick: Ask “Why?” five times to find root cause.

85. Permit to Work (PTW)

Meaning: Formal system ensuring high-risk work is safe.
Truth: PTW is NOT a document - it is a process.

Environmental Legal & Compliance Terms (25 Terms)

Common Global EHS Terms (Seen in MNCs)

• GHS (Globally Harmonized System): Standard chemical labelling system used worldwide

• HazCom: Process of informing workers about chemical hazards

• Industrial Hygiene: Controlling exposure to dust, fumes, noise, chemicals

86. Consent to Establish (CTE)

Meaning: Permission from the State Pollution Control Board (SPCB) to set up a new industry or expand an existing one.
Stage: Taken before construction/installation.
Memory trick: CTE = “Permission to start building.”

Read more about How to read SPCB Consent

87. Consent to Operate (CTO)

Meaning: Permission to operate after confirming pollution control systems are in place.
Renewal: Typically every 1–5 years depending on category.
Industry Expert’s reminder: “Always check renewal dates first during compliance audits.”

88. EC (Environmental Clearance)

Meaning: Approval required for larger / high-impact industries or infrastructure projects.
Authority: SEIAA / MoEF&CC.
Common misunderstanding: EC ≠ Consent. EC is separate, higher-level permission.

89. CPCB (Central Pollution Control Board)

Meaning: National regulatory authority for environmental standards.
Role: Sets rules, monitors pollution, guides state boards.
Memory trick: CPCB = Chief Pollution Control Boss.

90. SPCB (State Pollution Control Board)

Meaning: State authority responsible for implementing environmental laws.
Examples: MPCB, GPCB, KSPCB.
Where you deal with them: CTE, CTO, BMW, HW, returns, inspections.

91. MoEF&CC

Meaning: Ministry of Environment, Forest and Climate Change.
Role: Policy-making, issuing ESG & environmental guidelines.
Memory trick: Mother of Environmental Frameworks & Climate Control.

92. Environmental Audit

Meaning: Independent assessment of compliance with environmental regulations.
Types: Internal, Third-party.
Best practice: Keep a separate “evidence folder” for all conditions.

93. EIA (Environmental Impact Assessment)

Meaning: Study to predict environmental impacts before starting a project.
Includes: Baseline data, modelling, risk assessment, EMP.
Critical: Public hearing process for large projects.

94. EMP (Environmental Management Plan)

Meaning: A plan detailing mitigation measures for impacts identified in EIA.
Memory trick: EMP = “Execution Master Plan”.

95. Form I (EC Application Form)

Meaning: Main application form for Environmental Clearance.
Contains: Project details, impact assessment info.

96. Hazardous Waste Rules

Meaning: Legal rules governing generation, storage, transport, and disposal of hazardous waste.
Important: Authorization required before generating HW.

97. BMW Rules (Bio-Medical Waste Rules)

Meaning: Rules for handling biomedical waste.
Industries forget: Medical room waste is governed by BMW rules too.

98. Plastic Waste Rules

Meaning: Regulations for producers, brand owners, and users of plastic packaging.
Key term: EPR (Extended Producer Responsibility).

Read more about SME Plastic Waste EPR Guide if you are a Brand Owner

99. EPR (Extended Producer Responsibility)

Meaning: Responsibility on producer to manage end-of-life waste (plastic/e-waste).
Example: FMCG companies collecting equivalent waste through PROs.

100. Annual Environmental Statement (Form V)

Meaning: Mandatory annual report summarising environmental performance.
Submission: On or before 30 September for the financial year ending 31 March.
Mistake: Many companies fill it like a formality - regulators notice & Confusing the Form V deadline with the 30 June Form IV annual-return deadline.

Read Form 5 Environmental Statement India: Example & Mistakes

101. Stack Monitoring Report

Meaning: Emission analysis report for boiler/DG/furnace stacks.
Frequency: Quarterly or monthly depending on sector.
Audit issue: Missing calibration certificates.

102. Ambient Air Quality Monitoring Report

Meaning: Air quality around industry premises.
Important for: Construction projects, large manufacturing clusters.

103. Water Cess / Environmental Cess

Meaning: Charge levied on industries for water consumption (under old rules).
Note: Replaced in many states but concept still understood by auditors.

104. ETS (Emissions Trading Scheme)

Meaning: Cap-and-trade system for emissions.
Example: Gujarat ETS for particulate pollution.

105. ODS (Ozone-Depleting Substances)

Meaning: Chemicals that damage the ozone layer (CFCs, HCFCs).
Rule: Prohibited or phased-out chemicals under Montreal Protocol.

106. White Category Industries

Meaning: Industries with negligible pollution potential.
Examples: Pencil manufacturing, optical frames.
Good news: No CTE/CTO required in many states.

107. Green Category Industries

Meaning: Low pollution potential but still regulated.
Example: Food processing without boilers, small assembly units.

108. Orange Category Industries

Meaning: Moderate pollution potential.
Common industries: Metal fabrication, textile processing.

109. Red Category Industries

Meaning: High pollution potential.
Examples: Chemical manufacturing, pharma, large dye units.
Important: Strictest rules + more frequent inspections.

110. Online Consent Management System (OCMS)

Meaning: Portal for applying CTE/CTO, BMW, HW permissions.
Industry pain point: Portal downtime close to deadline days.

111. Show Cause Notice (SCN)

Meaning: A notice asking industry to explain why action should not be taken for non-compliance.
Best practice: Respond within time + attach evidence + be factual, not emotional.

112. Closure Direction

Meaning: Order to stop operations due to major non-compliance.
Industry Expert’s advice: “Prevent closure with proactive compliance, not begging afterward.”

Monitoring & Sampling Terms (25 Terms)

113. Sampling Point

Meaning: The designated location on a stack or duct where emission sampling must be done.
Best practice: Ensure adequate straight length before and after the point (as per IS/USEPA guidelines).
Common mistake: Sampling from bends → unreliable results.

114. Pitot Tube

Meaning: Instrument used to measure velocity pressure inside a stack/duct.
Memory trick: Pitot = Pressure Probe used for airflow.

115. Velocity Profile

Meaning: Measurement of gas velocities at multiple points across stack diameter.
Reason: Ensures flow is uniform and sampling is representative.

116. Traverse Points

Meaning: Specific points inside stack where readings are taken for accuracy.
Industry Expert’s rule: “Never trust a single-point reading in a big chimney.”

117. Gas Flow Rate

Meaning: Total volume of gas passing through a stack per hour.
Importance: Used for emission load calculations (kg/hr).

118. Isokinetic Ratio

Meaning: Ratio of sampling velocity to actual gas velocity.
Target: Close to 1.0 (perfect isokinetic).
If >1 → over-sampling; if <1 → under-sampling.

119. Particulate Matter Filter Paper

Meaning: Special glass microfibre paper used to capture dust during stack monitoring.
Tip: Always weigh before and after sampling in controlled lab conditions.

120. Desiccator

Meaning: Airtight chamber used to cool and store filter papers without moisture gain.
Mistake: Keeping lid open for long → moisture ruins readings.

121. Silica Gel

Meaning: Moisture absorber used inside sampling equipment.
When to replace: If colour changes (blue → pink or orange → green depending on type).

122. Impinger Bottle

Meaning: Glass bottle used to absorb gaseous pollutants like SO₂, NO₂, HCl.
Important: Use correct absorbing solution for each pollutant.

123. Absorbing Solution

Meaning: Chemical solution used to absorb specific gases.
Examples:

• H₂O₂ for SO₂
• NaOH for HCl
• KMnO₄ for NO₂
  Mistake: Using wrong solution → zero readings.

124. Stack Diameter

Meaning: Width of chimney/duct at sampling point.
Use: Required for calculating flow rate.
Memory trick: Bigger diameter = slower velocity (for same flow).

125. Static Pressure

Meaning: Pressure exerted by gas when not moving.
Used with dynamic pressure to calculate velocity.

126. Dynamic Pressure

Meaning: Pressure due to moving gas.
Measured using pitot tube.
Formula: Directly linked to velocity.

127. Ambient Monitoring Station

Meaning: Temporary setup for 24-hour ambient air sampling (PM10, PM2.5, SO₂, NOx).
Tip: Avoid placing near obstructions like walls or trees.

128. Respirable Dust Sampler (RDS)

Meaning: Machine used to measure PM10 in ambient air.
Key: 24-hour sampling as per NAAQS guidelines.

129. Fine Particulate Sampler (FPS)

Meaning: Used for PM2.5 measurement.
Uses special filter paper and controlled flow rate.

130. Stack Monitoring Kit

Meaning: Complete set including pitot tube, probe, impingers, filter holder, pump.
Checklist: Ensure no leakage in connections before sampling.

131. Calibration Certificate

Meaning: Document showing instruments were calibrated by authorized lab.
Critical: Without calibration, regulators may reject reports.

132. Zero Calibration

Meaning: Setting instrument baseline with zero pollutant input.
Mistake: Skipping zero calibration before ambient monitoring.

133. Span Calibration

Meaning: Checking instrument response against a known pollutant concentration.
Important for: CEMS, gas analysers.

134. Grab Sample

Meaning: Single-moment sample of air or water.
Use: Instant analysis, quick checks.
Limitation: Not representative for variations.

135. Composite Sample

Meaning: Mixture of several samples taken over time.
Advantage: Represents average pollution level.

136. Online Monitoring Data

Meaning: Real-time emission/effluent data sent to SPCB servers.
Industry pain: Connectivity issues → auto-non-compliance alerts.

137. Stack Height

Meaning: Height of chimney above ground.
Reason: Ensures proper dispersion of pollutants.
Rule of thumb: Higher stack = better dispersion.

138. Effluent Flow Meter

Meaning: Measures treated effluent discharge quantity.
Important for: Monthly returns, load calculations.

139. Portable Gas Detector

Meaning: Handheld device to detect gases like H₂S, CO, O₂, VOCs.
Must use: Before confined space entry.

140. Personal Sampler

Meaning: Small sampler worn by workers to measure exposure to dust/fumes.
Used for: Occupational health monitoring.

PPE, Training & Behavioural Safety Terms (25 Terms)

141. Behaviour-Based Safety (BBS)

Meaning: A safety approach focused on observing worker behaviour and correcting unsafe habits.
Key idea: People don’t change because of rules; they change because of awareness and reinforcement.
Industry Expert’s line: “Safety is 80% behaviour, 20% equipment.”

142. Safety Culture

Meaning: Shared attitudes, beliefs, and values about safety in an organisation.
Indicator: Workers follow safety even when no one is watching.
Memory trick: Culture = ‘How we behave when nobody checks’.

143. PPE (Personal Protective Equipment)

Meaning: Safety gear worn by workers - helmet, gloves, goggles, shoes, masks.
Truth: PPE is the last line of defence, not the first.
Common mistake: Treating PPE as primary safeguard.

144. Helmet / Hard Hat

Meaning: Protects the head from impact and falling objects.
Checklist: Chin strap, no cracks, proper fit.
Mistake: Wearing it loosely “because it's hot.”

145. Safety Shoes

Meaning: Footwear with steel or composite toe for protection.
Important: Anti-slip sole and ankle support.
Tip: Replace worn-out soles immediately.

146. Safety Goggles / Face Shield

Meaning: Protects eyes/face from chemical splashes or flying particles.
Rule: Goggles for chemical handling, face shield for grinding/cutting.

147. Ear Plugs / Ear Muffs

Meaning: Protects ears from high noise in DG rooms, compressors, etc.
Tip: Prolonged exposure to 90+ dB equals long-term hearing loss.

148. Masks / Respirators

Meaning: Prevent inhalation of dust, fumes, vapours, gases.
Types: N95, cartridge-type, full-face respirators.
Mistake: Using N95 for solvent fumes - wrong PPE.

149. Gloves (Chemical / Heat / Cut-resistant)

Meaning: Protects hands from specific hazards.
Golden rule: One glove cannot protect against all hazards.

150. Safety Harness (Full Body)

Meaning: PPE used in work-at-height to prevent falls.
Check: Lanyard strength, D-ring, stitching, expiry.

151. Anti-Static Clothing

Meaning: Prevents buildup of static electricity.
Use: Paint booths, explosive atmospheres.

152. Fire-Resistant (FR) Clothing

Meaning: Clothing designed to self-extinguish after flame exposure.
Used in: Oil & gas, petrochemical, welding areas.

153. Toolbox Talk (TBT)

Meaning: Short pre-work safety briefing to refresh awareness.
Best practice: Keep it simple, practical, and relevant to today’s tasks.

154. Job Safety Analysis (JSA)

Meaning: Step-by-step identification of risks in a specific job.
Parts: Job steps → Hazards → Controls.
Memory trick: JSA = Job-Specific Awareness.

155. Permit to Work (PTW)

Meaning: Formal approval before starting high-risk work.
Includes: Hot work, confined space, electrical, work at height.
Truth: A permit is a process, not a paper.

156. Safety Audit

Meaning: Systematic inspection of workplace safety practices.
Types: Internal / External.
Mistake: Treating audit as fault-finding instead of improvement.

157. Fire Mock Drill

Meaning: Simulation of fire emergency to prepare workers.
Goal: Reduce panic and improve evacuation time.
Important: Conduct at least once every 6 months.

158. Evacuation Plan

Meaning: Map showing escape routes, assembly points, emergency contacts.
Tip: Should be displayed in all major areas.

159. Safety Induction

Meaning: Mandatory safety briefing for new employees or contractors.
Why needed: 50% of accidents involve newly joined personnel.

160. Contractor Safety Management

Meaning: Ensuring contractors follow the same safety standards as company employees.
Issue: Many accidents involve contractors due to lack of supervision.

161. Safety Committee

Meaning: A group of management + worker representatives working on safety improvements.
Advantage: Workers report hazards faster through committees.

162. Incident Reporting System

Meaning: Platform/process to report near-misses, unsafe acts, unsafe conditions.
Tip: Encourage anonymous reporting.

163. Emergency Response Team (ERT)

Meaning: Trained personnel who handle emergencies like fire, spill, injury.
Required in: Medium & large industries.

164. HAZOP (Hazard and Operability Study)

Meaning: A structured study to identify potential hazards in processes.
Used mainly in: Chemical, petrochemical, pharma industries.

165. Behavioural Observation

Meaning: Regular observation of workers to identify unsafe habits.
Goal: Coaching → not punishing.

Bonus Memory Tricks, Incidents & Long-Term Retention Hacks (20 Items)

This final part is designed to make juniors remember EHS terms for life - using humour, pattern memory, real incidents, and Industry Expert-style wisdom.
Exactly the kind of content people will remember and associate with EHSSaral.

166. The “Traffic Light Rule” for Hazard Categories

Green = Safe
Orange = Moderate
Red = High risk
Memory trick: Just like Indian states classify industries - Green, Orange, Red.
Easy to recall during audits or interviews.

167. The “3 Gas Rule” for Air Pollution

If confused in stack testing, remember:

• SO₂ = throat burning
• NOx = reddish-brown
• CO = invisible but deadly
  This simple 3-gas recall helps juniors instantly identify issues.

168. PM10 vs PM2.5 Shortcut

PM10 = “Tenants at the entrance” → nose & throat
PM2.5 = “Guests who enter your home without asking” → deep lungs

169. COD vs BOD Difference in 5 Seconds

COD = Faster, Higher
BOD = Slower, Lower
That’s it. This is enough to answer most interview questions.

170. SDS = “Google Map for Chemicals”

Just like Maps guides you on the road, SDS guides you during chemical handling.
You will never forget this again.

171. Ventilation Test for VOCs

If a room feels “hot + smelly + headache”- assume VOC.
Even experienced EHS officers use this rule for quick diagnosis.

172. Sludge Behaviour Trick

SVI high = bulking
SVI low = pin-floc
SVI normal = perfect settling
Memory: SVI = “Sludge’s VIP Identity.”

173. The “One Glove Doesn’t Fit All” Rule

Chemical gloves ≠ heat gloves ≠ cut-resistant gloves.
This is the #1 mistake in Indian industries during audits.

174. The “10 Second Confined Space Test”

If the place:

• has poor ventilation
• has only one entry
• feels humid/musty

Treat it as confined space until proven otherwise.

175. The “3 Why Rule” for Incident Investigation

Ask “Why?” three times.
You will usually find the root cause by the third level.

176. Fire Triangle Memory Trick

Fuel + Heat + Oxygen
Remove ONE → No fire
This is the foundation of firefighting logic in every industry.

177. The “Two Smells You Never Ignore” Rule

• Rotten egg smell → Hydrogen sulphide (H₂S)
• Bitter almond smell → Cyanide (sometimes undetectable)
  Industry Expert’s warning: “Smell is your first detector.”

178. The “Posting Mistake” in Reports

Many EHS juniors mix:
Ambient report → NAAQS
Stack report → SPCB norms
Effluent → GSR 596(E) or state norms
This simple correction improves audit scores drastically.

179. The “Left-Right” Labelling Trick

Left arrow = Inlet
Right arrow = Outlet
This trick helps while preparing diagrams for ETP/STP flow or reports.

ETP & STP Troubleshooting: The Complete Indian Guide

180. The “Don’t Trust Colour” Rule

Clear water ≠ clean water
Some of the worst industrial pollutants are colourless.
Always test, never assume.

181. The “Back-Up Brain” Habit

Before audit → keep digital copies of:

• consent
• calibration certs
• Form V
• HW authorization
• SDS
  This alone reduces 70% of compliance panic.

182. The “PPE Rotation Rule”

Helmet: Change every 3 years
Safety shoes: 6–12 months
Goggles: When scratched
Gloves: Before each job
Never let PPE expire silently.

183. The “Noise Memory” Test

• 85 dB: you have to raise your voice
• 90 dB: you shout
• 100+ dB: communication impossible
  Easy way to judge noise levels without an instrument.

184. The “Two-Minute Tank Rule”

Before entering any tank/pit:
Stand for 2 minutes, observe humidity/smell.
If uncomfortable → STOP.
Your instinct saves lives.

185. The “Industry Expert’s Final Lesson”

“Safety is not inspection.
Safety is preparation.
Inspection only reveals what preparation forgot.”
This line alone shapes the mindset of thousands of juniors.

CONCLUSION – THE EHS MINDSET FOR LIFE

Understanding 150 EHS terms is not about passing an audit or an interview.
It’s about building situational intelligence, the ability to see risk before others do.

EHS is not a job.
It is a responsibility -
towards workers, towards citizens around industrial zones,
and towards Bharat’s environmental safety.

EHSSaral exists so that every junior officer, manager, and industry can get clarity, confidence, and control over compliance.

This glossary is not just information -
it is a mentor in text form.

10 Basic Safety Rules in Any Industry

1. No PPE = No work

2. Never bypass safety devices

3. Take permits seriously

4. Report near misses

5. Test before confined space entry

6. Lockout before maintenance

7. Housekeeping prevents accidents

8. Follow SOPs, not shortcuts

9. Stop unsafe work

10. Safety before speed

Frequently Asked Questions:

Q1. What are the most important EHS terms for beginners?

Ans: PM2.5, PM10, BOD, COD, PPE, JSA, CTE, CTO, Hazardous Waste, Stack Monitoring, VOC, MLSS, Sludge Volume Index, etc.

Q2. What is the difference between BOD and COD?

Ans: COD is faster and usually higher; BOD measures only biodegradable organic matter.

Q3. What does PM2.5 mean in air pollution?

Ans: Particulate matter smaller than 2.5 microns that enters deep into the lungs.

Q4. What is the purpose of a Confined Space Permit?

Ans: To ensure the atmosphere is safe before entry and to prevent accidents.

Q5. Why is SDS important in industries?

Ans: SDS gives key information on hazards, PPE, storage, emergency actions and first aid.

Q6. What is Consent to Operate (CTO)?

Ans: Permission from SPCB to run industry after ensuring pollution control systems are installed.

Q7. What is a Hazardous Waste Manifest?

Ans: A tracking document that monitors HW movement from generator to TSDF.