Master the full environmental side of EHS — air quality, water protection, hazardous waste, contaminated land, climate compliance, and building an ISO 14001 environmental management system from scratch.
The US Clean Air Act is the most comprehensive air pollution law in the world. Understanding its structure is essential for any facility with air emissions.
The Clean Air Act (CAA) is organised into six major titles. Each title delegates specific authorities to the EPA and creates specific obligations for facilities. The 1990 amendments were the most significant overhaul, adding Titles IV–VI.
National Ambient Air Quality Standards (NAAQS) for 6 criteria pollutants. State Implementation Plans (SIPs). Nonattainment area requirements. New Source Review (NSR) permitting.
Major sources of air pollution must obtain Title V operating permits. Consolidates all CAA requirements into a single permit. State-issued but EPA-approved. Requires annual compliance certifications.
187 listed Hazardous Air Pollutants (HAPs). National Emission Standards for Hazardous Air Pollutants (NESHAPs). Maximum Achievable Control Technology (MACT) standards for major sources.
Cap-and-trade program for SO₂ and NOₓ emissions from power plants. First large-scale emissions trading program in the US — model for later greenhouse gas trading schemes.
Implements the Montreal Protocol obligations. Phase-out of ozone-depleting substances (ODSs): CFCs, HCFCs, halons. Refrigerant management, technician certification (Section 608).
Emission standards for cars, trucks, non-road engines, and fuels. Corporate Average Fuel Economy (CAFE) standards coordinated with DOT. Reformulated gasoline requirements.
The National Ambient Air Quality Standards (NAAQS) set concentration limits for six "criteria" air pollutants. Primary NAAQS protect public health; secondary NAAQS protect public welfare (crops, visibility, ecosystems). States must achieve these standards through State Implementation Plans (SIPs).
| Pollutant | Primary NAAQS Standard | Averaging Time | Health Effects | Major Sources |
|---|---|---|---|---|
| PM2.5 (Fine Particles) | 9 µg/m³ (annual, revised 2024); 35 µg/m³ (24-hr) | Annual / 24-hr | Cardiovascular & respiratory disease, premature death | Combustion, vehicles, power plants, wildfires |
| PM10 (Coarse Particles) | 150 µg/m³ | 24-hour | Respiratory effects, aggravated asthma | Dust, construction, mining, agriculture |
| Ozone (O₃) | 0.070 ppm | 8-hour | Lung damage, asthma, reduced lung function | Secondary pollutant — formed from NOₓ + VOCs + sunlight |
| Carbon Monoxide (CO) | 9 ppm (8-hr); 35 ppm (1-hr) | 8-hour / 1-hour | Reduces O₂ delivery to organs; fatal at high concentrations | Vehicles, combustion equipment, industrial processes |
| Sulfur Dioxide (SO₂) | 75 ppb | 1-hour | Respiratory irritation; acid rain formation | Power plants, smelters, fuel combustion |
| Nitrogen Dioxide (NO₂) | 53 ppb (annual); 100 ppb (1-hr) | Annual / 1-hour | Lung inflammation; precursor to ozone and PM2.5 | Vehicles, power plants, industrial boilers |
| Lead (Pb) | 0.15 µg/m³ | Rolling 3-month avg | Neurological damage; especially harmful to children | Smelters, battery manufacturing, aviation fuel |
2024 PM2.5 Standard Revision: In February 2024, EPA revised the annual PM2.5 NAAQS from 12 µg/m³ to 9 µg/m³ — the most significant air quality rule update in a decade. This will require many areas to develop new State Implementation Plans and may trigger additional permit requirements for major industrial sources. Ref: 89 FR 16202 (March 6, 2024)
Not every facility needs an air permit, but those that do face complex obligations. Understanding the thresholds is a core EHS competency.
| Permit Type | Applicability Threshold | Key Requirements | Authority |
|---|---|---|---|
| Title V Major Source Operating Permit | ≥100 TPY of any regulated pollutant (10/25 TPY in non-attainment areas for some pollutants); or ≥10 TPY of any single HAP or ≥25 TPY of combined HAPs | Comprehensive permit consolidating all CAA requirements; annual compliance certification; public notice; EPA review | 40 CFR Part 70/71 |
| Prevention of Significant Deterioration (PSD) — Major New Source | New major source or major modification in attainment area. Thresholds: 100–250 TPY depending on source category | Best Available Control Technology (BACT); air quality analysis; pre-construction permit from State | 40 CFR Part 52 |
| Non-Attainment NSR | New or modified major source in a non-attainment area | Lowest Achievable Emission Rate (LAER) — more stringent than BACT; emission offsets required (>1:1 ratio) | 40 CFR Part 51 |
| Minor Source / State Permit | Below major source thresholds — varies by state | State-specific requirements; often less rigorous than Title V but still legally binding | State air agency |
For EHS professionals working in Europe, the EU has its own comprehensive air quality regulatory framework.
EU Directive 2008/50/EC sets limit values for PM2.5, PM10, NO₂, SO₂, CO, ozone, and benzene. Member states must develop Air Quality Plans for exceedance areas. Currently under revision (2022 proposal aligns more closely with WHO 2021 guidelines).
EU Directive 2010/75/EU (IED) requires large industrial plants to use Best Available Techniques (BAT). BAT Reference Documents (BREFs) published for each industry sector. Integrated Environmental Permit required.
EU Emissions Trading System covers ~40% of EU greenhouse gas emissions. Installations above threshold must surrender allowances equal to annual emissions. Phase IV (2021–2030) tightens caps annually. Linked to Paris Agreement targets.
Protecting surface water, groundwater, and drinking water — the regulatory framework, permit system, and spill prevention requirements.
The Clean Water Act (CWA, 1972) established the basic structure for regulating discharges of pollutants into US waters and for setting water quality standards. Its goal: "fishable and swimmable" waters nationwide.
"The objective of this Act is to restore and maintain the chemical, physical, and biological integrity of the Nation's waters."
The NPDES permit program (Section 402) is the primary mechanism for controlling water pollution. Any discharge of a pollutant from a point source to navigable waters requires an NPDES permit.
Ref: CWA §402 / 40 CFR Parts 122–125
Facilities with aboveground oil storage capacity ≥1,320 gallons (or underground storage ≥42,000 gallons) that could reasonably discharge oil to navigable waters must prepare and implement an SPCC Plan.
Ref: 40 CFR Part 112 — revised 2002, amended 2013
Section 404 requires a permit from the US Army Corps of Engineers (USACE) for discharge of dredged or fill material into "waters of the United States," including wetlands. Construction projects near water bodies must determine jurisdictional status.
Ref: CWA §404 / 33 CFR Parts 320–330
The SDWA (1974, 42 U.S.C. §300f) regulates public water systems and protects drinking water quality.
Ref: SDWA 42 U.S.C. §300f / 40 CFR Parts 141–149
The EU Water Framework Directive (WFD) establishes a framework for all water policy in Europe — integrated management of all water bodies to achieve "good status" by defined deadlines.
EU Directive 2000/60/EC requires member states to achieve "good ecological and chemical status" for all surface and groundwater bodies. River Basin Management Plans (RBMPs) are the primary planning instrument. Catchment-based approach — not political boundaries.
Priority Substances Directive (2013/39/EU) sets environmental quality standards (EQS) for 45 priority substances in water. Facilities discharging to water bodies must comply with these standards through their IPPC/IED permits.
Urban Wastewater Treatment Directive (91/271/EEC) requires secondary treatment for agglomerations above 2,000 population equivalents; more advanced treatment in sensitive areas. Currently under revision (2022 recast proposal).
PFAS — the emerging water crisis: Per- and polyfluoroalkyl substances (PFAS) are a group of ~12,000 synthetic chemicals found in firefighting foam (AFFF), non-stick cookware, and countless industrial products. They do not break down in the environment ("forever chemicals"). In April 2024, EPA set the first MCLs for PFOA and PFOS at 4 parts per trillion (ppt) — the lowest enforceable drinking water standard in US history. Many industrial sites face significant PFAS remediation liability. Ref: PFAS National Primary Drinking Water Regulation (2024)
Cradle-to-grave management of hazardous waste under RCRA — identification, generator classification, storage, manifesting, and disposal.
Not all industrial waste is hazardous under RCRA. Correctly identifying whether a material is a RCRA hazardous waste is the first and most critical step — misclassification creates both liability and compliance risk.
RCRA's definition of "solid waste" is very broad — it includes liquids, semi-solids, and gases in containers, not just solids. Materials that are recycled in certain ways may be excluded from the definition of solid waste. Ref: 40 CFR §261.2
Many common industrial materials are excluded from RCRA hazardous waste regulation: domestic sewage, irrigation return flows, nuclear material (regulated under AEA), household hazardous waste, mining wastes (Bevill exclusion), and certain recycled materials. Ref: 40 CFR §261.4
EPA has listed specific wastes as hazardous. Four lists: F-list (non-specific source wastes — spent solvents, electroplating baths); K-list (specific source wastes — petroleum refining, pesticide manufacturing); P-list (acutely hazardous discarded commercial chemicals); U-list (toxic discarded commercial chemicals). Ref: 40 CFR §§261.30–261.33
If not listed, test for four characteristics: Ignitability (D001) — flash point <60°C; Corrosivity (D002) — pH ≤2 or ≥12.5; Reactivity (D003) — unstable, reacts violently; Toxicity (D004–D043) — TCLP test for 40 regulated constituents. Ref: 40 CFR §§261.21–261.24
How much hazardous waste you generate per calendar month determines your generator category. The 2016 Generator Improvements Rule (effective 2018) revised the three categories. Each category carries different accumulation time limits, storage requirements, and reporting obligations.
Fewest requirements. No time limit for accumulation. Must send waste to permitted facility. Cannot accumulate >1,000 kg on-site at any time. No EPA ID required unless shipping off-site. Ref: 40 CFR Part 262 Subpart L
Can accumulate up to 270 days on-site. Must have EPA ID number. Emergency coordinator required. Must use manifest for off-site shipments. Annual reporting to state. Ref: 40 CFR Part 262 Subpart L
Strictest requirements. 90-day accumulation limit (120 days for remote sites). Emergency coordinator on-site 24/7. Written contingency plan. Biennial reporting. Land Disposal Restrictions (LDR) apply. Full training program. Ref: 40 CFR Part 262 Subpart B
The Uniform Hazardous Waste Manifest (EPA Form 8700-22): Any off-site shipment of hazardous waste requires a Uniform Hazardous Waste Manifest — a tracking document that accompanies the waste from generator to final disposal and ensures every party in the chain is authorised and accountable. Generators must retain copies for 3 years. Transporters must carry manifests. TSDFs must sign and return copies. Electronic manifests (e-Manifests) are now available through EPA's RCRAInfo system. Ref: 40 CFR Part 262 Subpart B
RCRA's Land Disposal Restrictions (LDRs) prohibit placing untreated hazardous waste directly into the land. Waste must be treated to meet specified treatment standards before land disposal. This is a fundamental principle of RCRA's cradle-to-grave system.
EPA specifies either a treatment method (e.g., incineration, stabilisation) or a concentration-based standard for each waste code. Treatment must achieve the standard before land disposal (landfill, surface impoundment, land application).
Generators must send an LDR notification/certification to the TSDF with each waste shipment, certifying that the waste meets treatment standards or identifying the waste codes and applicable standards.
TSDFs must have a RCRA permit, meet extensive design and operating standards, carry financial assurance for closure and post-closure, and maintain groundwater monitoring programs.
The Basel Convention (1989) controls the transboundary movements of hazardous waste and their disposal. 190 parties. The US has signed but not ratified the Basel Convention — but US exporters must comply with requirements of receiving countries.
Basel Ban Amendment (2019 in force): Prohibits export of hazardous waste from OECD countries to non-OECD countries. The 2019 "Plastic Waste Amendments" added certain plastic wastes to the controlled list — companies exporting plastic waste must now obtain prior informed consent from importing countries. The EU implements Basel through Regulation (EC) No 1013/2006 on shipments of waste. Ref: Basel Convention (1989)
Superfund liability, contaminated site remediation, brownfields, and the Phase I/II Environmental Site Assessment process used in every property transaction.
CERCLA (1980) gives EPA the authority to clean up contaminated sites and hold responsible parties liable for cleanup costs. Its liability scheme is unique — and uniquely powerful. No other environmental law creates this level of financial exposure.
CERCLA liability is strict, joint, several, and retroactive. Strict = no need to prove negligence — if you released a hazardous substance, you are liable. Joint and several = any single Potentially Responsible Party (PRP) can be held liable for the entire cleanup cost. Retroactive = applies to releases that occurred before CERCLA was enacted (1980). This means a company that legally disposed of waste decades ago can be held liable for millions in cleanup costs today. Ref: CERCLA §107 / 42 U.S.C. §9607
1. Current owners/operators of the facility. 2. Past owners/operators at time of disposal. 3. Generators who arranged for disposal (sent waste there). 4. Transporters who selected the site. All four can be pursued for the full cleanup cost.
Sites scoring high on the Hazard Ranking System (HRS) are listed on the NPL — the Superfund list. Over 1,300 current NPL sites. Average cleanup cost: $15–50 million per site. Some multi-billion dollar sites (e.g., Hanford, Anaconda Copper).
The RI characterises nature and extent of contamination. The FS evaluates cleanup alternatives. The Record of Decision (ROD) selects the remedy. A typical RI/FS takes 3–7 years and costs millions before any cleanup begins.
Brownfields are properties where redevelopment is complicated by real or potential contamination. EPA's Brownfields Program provides grants and liability protections to facilitate cleanup and reuse of contaminated properties — reducing Superfund liability for bona fide purchasers.
Before purchasing any property where industrial operations occurred, a Phase I Environmental Site Assessment (ESA) is performed. It is the standard of care for CERCLA's "bona fide prospective purchaser" defence — without it, a buyer can inherit full Superfund liability.
Non-invasive assessment. Reviews historical records (Sanborn maps, aerial photos, government databases, title records), interviews current/former owners, and conducts a visual site inspection. Identifies Recognised Environmental Conditions (RECs). Standard: ASTM E1527-21 (updated 2021). No sampling — paper and observation only. Must be conducted by an Environmental Professional (EP).
Triggered by RECs identified in Phase I. Invasive investigation — soil borings, groundwater monitoring wells, soil/water/soil gas sampling, laboratory analysis. Determines if contamination is present, its extent, and concentration. May trigger CERCLA notification obligations if releases are confirmed above reportable quantities.
If Phase II confirms contamination above regulatory thresholds, remediation is designed and implemented. Technologies include: pump-and-treat for groundwater, soil excavation, soil vapour extraction, bioremediation, in-situ chemical oxidation, and monitored natural attenuation (MNA). Cleanup standards vary by future land use (residential vs. industrial).
ASTM E1527-21 (2021 update) updated the Phase I ESA standard with new requirements for reviewing emerging contaminants like PFAS, clarifying Controlled RECs (CRECs) and Historical RECs (HRECs), and updating the "file review" requirements. Any Phase I ESA conducted after February 2023 should follow the 2021 standard to qualify for CERCLA innocent landowner defences. Ref: ASTM E1527-21 CERCLA §101(35)(B)
GHG reporting, carbon markets, Scope 1/2/3 emissions, the Paris Agreement, and SEC climate disclosure — the fastest-growing area in EHS.
EHS professionals must understand GHG reporting and the concept of CO₂ equivalents (CO₂e). Each gas has a Global Warming Potential (GWP) measured relative to CO₂ over a 100-year time horizon (GWP100). Referenced to IPCC Sixth Assessment Report (AR6, 2021).
| Gas | Chemical Formula | GWP100 (IPCC AR6) | Main Industrial Sources | Kyoto Protocol Listed? |
|---|---|---|---|---|
| Carbon Dioxide | CO₂ | 1 (baseline) | Fossil fuel combustion, industrial processes, deforestation | Yes |
| Methane | CH₄ | 29.8 | Natural gas systems, livestock, landfills, coal mining | Yes |
| Nitrous Oxide | N₂O | 273 | Agriculture (fertilisers), combustion, industrial processes | Yes |
| HFCs (group) | Various | 12–14,800 | Refrigeration, air conditioning (replaced CFCs/HCFCs) | Yes (Kigali Amendment) |
| PFCs (group) | Various | 6,630–11,100 | Aluminium smelting, semiconductor manufacturing | Yes |
| Sulfur Hexafluoride | SF₆ | 25,200 | Electrical switchgear (highest GWP of all regulated gases) | Yes |
| Nitrogen Trifluoride | NF₃ | 17,400 | Semiconductor manufacturing (added by Doha Amendment) | Yes (Doha Amendment) |
The GHG Protocol Corporate Accounting and Reporting Standard (World Resources Institute/World Business Council for Sustainable Development, 2004) established the Scope 1/2/3 framework now used globally — by EPA, SEC, ISO 14064, and all major voluntary reporting frameworks (CDP, GRI, TCFD).
Emissions from sources owned or controlled by the organisation. Stationary combustion (boilers, furnaces), mobile combustion (company vehicles), process emissions (chemical reactions), fugitive emissions (refrigerant leaks, methane from pipelines).
Indirect emissions from generation of purchased electricity, heat, steam, or cooling consumed by the organisation. Location-based (grid average emissions factor) or market-based (contractual instruments — RECs, PPAs) methods per GHG Protocol Scope 2 Guidance.
All other indirect emissions in the value chain — 15 categories including purchased goods/services, capital goods, business travel, employee commuting, waste, use of sold products, end-of-life treatment. Typically 70–90% of a company's total GHG footprint. Mandatory for SEC climate disclosure for many companies.
The US EPA Greenhouse Gas Reporting Program (GHGRP) requires annual GHG reporting from facilities emitting ≥25,000 metric tons CO₂e/year. Covers 41 industrial source categories. Reports submitted to EPA's Electronic GHG Reporting Tool (e-GGRT) annually by March 31.
Ref: 40 CFR Part 98
Adopted at COP21 (Paris, December 2015). Legally binding under the UNFCCC. 195 parties. Core commitments:
Ref: Paris Agreement (2015) UNFCCC
In March 2024, the SEC adopted final rules requiring publicly listed US companies to disclose material climate-related risks, GHG emissions, and climate-related financial impacts in annual reports and registration statements.
Ref: 17 CFR Parts 210, 229, 230, 232, 239, 240, 249 (SEC Final Rule, March 2024)
ISO 14064 is the international standard for GHG quantification, monitoring, reporting, and verification at the organisational and project level.
Build a systematic approach to environmental compliance and performance improvement — the world's most widely adopted environmental management framework.
ISO 14001:2015 is the internationally recognised standard for Environmental Management Systems. Over 300,000 organisations in 170+ countries are certified. Like ISO 45001, it uses the Plan-Do-Check-Act structure. The 2015 version added requirements for lifecycle thinking, strategic context (Clause 4), and leadership (Clause 5).
"The purpose of this International Standard is to provide organisations with a framework to protect the environment and respond to changing environmental conditions in balance with socioeconomic needs."
ISO 14001 Clause 6.1.2 requires identification of environmental aspects — the elements of an organisation's activities, products, or services that interact with the environment — and evaluation of their significance. This is the environmental equivalent of hazard identification in OH&S.
Map all operations: manufacturing processes, utilities, waste generation, transport, office activities, maintenance, construction. Consider normal, abnormal (startup/shutdown), and emergency conditions. Include outsourced processes within the organisation's control.
For each activity, identify the aspect — the element that interacts with the environment. Examples: air emissions from combustion, wastewater discharge, solid waste generation, energy consumption, noise, land contamination, water use, raw material consumption.
Each aspect causes one or more impacts — changes to the environment. Examples: air emissions → air quality degradation; wastewater → water quality degradation; waste → landfill burden; energy → climate change contribution. Consider both actual and potential impacts.
Rate each aspect using criteria such as: severity of impact, probability of occurrence, scale (local, regional, global), reversibility, compliance obligations, stakeholder concern. Significant Environmental Aspects (SEAs) must be controlled through objectives, operational controls, or both.
ISO 14001 Clause 9.1 and ISO 14031:2021 (Environmental Performance Evaluation) provide the framework for measuring and communicating environmental performance. These are the metrics every EHS professional should track.
Total VOC emissions (kg/yr); NOₓ (tonnes/yr); GHG intensity (tonnes CO₂e/unit of production); Scope 1+2 absolute emissions (MTCO₂e/yr); compliance rate with permitted emission limits.
Total water withdrawal by source (m³/yr); water intensity (m³/unit); wastewater discharge volume and quality; percent recycled/reclaimed; water stress assessment (WRI Aqueduct tool).
Total waste generated (tonnes/yr); hazardous vs non-hazardous split; waste diversion rate (% recycled + recovered); waste intensity (kg/unit); zero-waste-to-landfill target tracking.
Total energy consumption (GJ/yr); energy intensity (GJ/unit); renewable energy percentage; Scope 2 market-based vs location-based emissions; energy reduction vs baseline.
Number of regulatory notices of violation; permit exceedances; environmental fines/penalties paid; compliance audit scores; corrective action closure rates; number of environmental incidents.
Area of land in or adjacent to protected areas or high-biodiversity areas; habitat disturbed/restored (ha); species affected; Taskforce on Nature-related Financial Disclosures (TNFD) metrics.
The EU Eco-Management and Audit Scheme (EMAS III, Regulation (EC) No 1221/2009) goes beyond ISO 14001 by requiring public environmental reporting via a verified Environmental Statement. Organisations registered with EMAS use the EMAS logo and demonstrate superior transparency.
EMAS vs ISO 14001: EMAS includes all ISO 14001 requirements plus: mandatory public Environmental Statement (verified by accredited environmental verifier); registration on the EU EMAS register; commitment to continual improvement evidenced by quantified targets; employee involvement requirements. About 4,000 organisations across Europe hold EMAS registration — it is the premium standard for environmental management credibility. Ref: EMAS III Reg. (EC) 1221/2009 (amended 2017)
Before major projects (factories, roads, ports, mines, power plants) are approved, an Environmental Impact Assessment is required to identify and mitigate significant environmental effects.
National Environmental Policy Act (1969) requires federal agencies to prepare Environmental Impact Statements (EIS) for "major Federal actions significantly affecting the environment." Most significant infrastructure projects go through NEPA review.
EU Directive 2011/92/EU (as amended by 2014/52/EU) requires EIA for projects listed in Annexes I and II. National competent authorities review EIA reports. Public consultation is mandatory. Screening and scoping procedures determine the level of assessment required.
International Finance Corporation Performance Standards (2012) are required for projects receiving IFC or Equator Principles financing globally. PS1 (Environmental and Social Assessment) and PS3 (Resource Efficiency) are particularly relevant for EHS professionals on international projects.
1. The EPA revised the annual PM2.5 National Ambient Air Quality Standard (NAAQS) in 2024. What is the new standard?
2. Under the Clean Water Act, the SPCC rule (40 CFR Part 112) requires a Spill Prevention, Control, and Countermeasure plan for facilities with aboveground oil storage above what threshold?
3. Under RCRA (40 CFR Part 261), which characteristic makes a waste D001 ignitable?
4. CERCLA liability is described as "strict, joint, several, and retroactive." What does "joint and several" mean in this context?
5. Under the GHG Protocol framework, which Scope covers indirect emissions from the generation of purchased electricity consumed by the organisation?
6. ISO 14001:2015 Clause 6.1.2 requires organisations to identify environmental aspects and determine which are "significant." What is the term used for an aspect that has or can have a significant environmental impact?
7. The Paris Agreement (2015) sets a global temperature target. What is the aspirational limit for global temperature rise above pre-industrial levels?