Environmental Audit for Facilities: Compliance & EHS Guide

What Is an Environmental Audit?

An environmental audit is a systematic, documented evaluation of a facility's compliance with applicable environmental laws, regulations, and standards, and the effectiveness of its environmental management controls. Unlike a green audit — which takes a broad, performance-oriented view of sustainability — an environmental audit focuses specifically on regulatory compliance and environmental risk management.

The environmental audit examines whether the facility's operations, practices, and controls meet the requirements imposed by environmental legislation, permit conditions, and industry standards. It identifies non-compliance issues, assesses environmental risks, and recommends corrective and preventive actions to bring the facility into full compliance and reduce its environmental liability.

Environmental audits have their origins in the 1970s and 1980s, when US companies began conducting voluntary compliance assessments to identify and correct regulatory violations before government inspectors found them. Today, environmental auditing is a mature discipline practiced worldwide, with established methodologies, professional qualifications, and regulatory requirements.

Types of Environmental Audits

• Compliance audit: The most common type — systematically checks adherence to all applicable environmental regulations, permits, and licence conditions.
• Environmental management system (EMS) audit: Evaluates the effectiveness of the organisation's EMS against ISO 14001 or a similar standard.
• Due diligence audit: Conducted during mergers, acquisitions, or property transactions to identify environmental liabilities.
• Contamination assessment: Focuses specifically on soil and groundwater contamination, typically for industrial sites with historical operations.
• Waste audit: Detailed assessment of waste generation, characterisation, handling, and disposal practices.

Difference from Green Audit

Understanding the distinction between environmental and green audits is critical for selecting the right assessment — or for properly sequencing them:

Audit Scope

A comprehensive environmental audit covers the following domains:

1. Air Emissions

The audit evaluates all sources of air pollution from the facility:

• Stack emissions: Emissions from boilers, furnaces, DG sets, incinerators, and process equipment. Monitoring for PM (particulate matter), SO2, NOx, CO, and process-specific pollutants (VOCs, HCl, HF, metals).
• Ambient air quality: Monitoring at the facility boundary and in surrounding areas for PM2.5, PM10, SO2, NOx, CO, O3, and lead — compared against National Ambient Air Quality Standards (NAAQS).
• Fugitive emissions: Uncontrolled emissions from leaks, open processes, material handling, and storage — particularly relevant for chemical plants, refineries, and facilities handling volatile materials.
• DG set emissions: Compliance with CPCB emission norms for diesel generator sets, stack height requirements, and operating hour restrictions.
• Indoor air quality: For educational institutions, offices, and healthcare facilities — CO2, PM2.5, temperature, humidity, and ventilation adequacy.

2. Water Discharge

• Effluent quality: Testing of treated effluent against discharge standards prescribed in the Consent to Operate. Parameters include pH, BOD, COD, TSS, TDS, oil and grease, heavy metals, and process-specific pollutants.
• Effluent treatment: Adequacy and effectiveness of ETP/STP systems — design capacity vs. actual load, treatment efficiency, maintenance records, sludge management.
• Discharge point compliance: Verification that discharge occurs only at authorised points and meets prescribed standards.
• Zero Liquid Discharge (ZLD): For facilities required to implement ZLD — verification of system operation and compliance.
• Groundwater quality: Monitoring of bore wells and open wells for contamination indicators, particularly near waste storage areas, fuel storage, and chemical handling zones.

3. Hazardous Waste Management

• Waste characterisation: Proper identification and classification of hazardous wastes as per the Hazardous and Other Wastes (Management and Transboundary Movement) Rules.
• Storage and handling: Compliance with storage duration limits (90 days or as per authorisation), proper containment, labelling, segregation of incompatible wastes, and access control.
• Manifest system: Complete and accurate hazardous waste manifests for all waste dispatched. Reconciliation between generation records and disposal records.
• Disposal: Verification that waste is sent only to authorised Treatment, Storage, and Disposal Facilities (TSDFs). Compliance with CPCB/SPCB-prescribed disposal methods.
• Authorisation: Valid Hazardous Waste authorisation from SPCB with correct waste categories and quantities.

4. Noise Pollution

• Workplace noise: Noise levels in production areas, utility rooms, and near major equipment — compared against occupational exposure limits (85 dBA for 8-hour TWA).
• Boundary noise: Noise levels at the facility boundary — compared against ambient noise standards for the zone category (industrial, commercial, residential, silence zone).
• DG set noise: Compliance with acoustic enclosure requirements for diesel generator sets.
• Noise control measures: Effectiveness of barriers, enclosures, vibration isolation, and hearing protection programmes.

5. Soil Contamination

• Risk areas: Assessment of soil contamination risk around fuel storage (underground and above-ground tanks), chemical storage, waste yards, historical disposal areas, and transformer locations (PCB risk).
• Sampling: Soil sampling at identified risk locations, testing for heavy metals, hydrocarbons, solvents, and other contaminants relevant to the facility's operations.
• Contamination history: Review of historical operations, spill records, and previous assessment reports.

6. Chemical Storage and Handling

• MSIHC compliance: Compliance with the Manufacture, Storage and Import of Hazardous Chemical Rules — notifications, safety reports, on-site emergency plans, MSDS availability.
• Storage conditions: Proper segregation of incompatible chemicals, secondary containment adequacy, ventilation, temperature control, fire protection, and access control.
• Safety Data Sheets: Availability and currency of SDS/MSDS for all chemicals used, stored, and handled on-site.
• Emergency response: Spill response procedures, spill kits, containment equipment, trained response teams, and drill records.

7. EHS Controls

• Occupational health: Medical surveillance programmes, exposure monitoring for workplace hazards (noise, dust, chemicals, heat), health records management.
• Safety systems: Fire detection and suppression, emergency exits, evacuation plans, electrical safety, machine guarding, lockout/tagout procedures.
• Training: EHS induction training, specialised training for hazardous operations, emergency response drills, and competence records.
• Incident management: Incident reporting, investigation, root cause analysis, corrective actions, and trend analysis.
• PPE management: Hazard-based PPE selection, availability, training, usage monitoring, and replacement protocols.

Regulatory Compliance Checks

The environmental audit systematically checks compliance with the following Indian environmental legislation:

Consent to Operate (CTO)

The Consent to Operate, issued by the State Pollution Control Board (SPCB), is the foundational environmental permit for most facilities. The environmental audit verifies:

• CTO validity — is it current and not expired?
• CTO conditions — are all conditions being met (emission limits, effluent standards, waste quantities, monitoring frequencies)?
• Scope changes — have any changes in operations, products, or capacity occurred that require CTO amendment?
• Annual returns — has the Annual Environmental Statement been submitted to SPCB as required?

Audit Methodology

A structured environmental audit follows these phases:

Phase 1: Planning and Preparation (1-2 Weeks)

• Define audit scope, objectives, and criteria.
• Compile applicable legal register — list of all environmental laws and regulations applicable to the facility.
• Request pre-audit documentation — permits, monitoring reports, waste manifests, compliance correspondence.
• Prepare audit checklists tailored to the facility type and regulatory context.
• Assemble audit team with appropriate expertise (air, water, waste, EHS).

Phase 2: Document Review (1 Week)

• Review all permits and authorisations for validity and completeness.
• Analyse environmental monitoring data against prescribed standards.
• Review compliance correspondence with CPCB/SPCB — notices, show-cause orders, directions.
• Evaluate waste management records — generation, storage, disposal manifests.
• Assess EHS training records, incident reports, and emergency preparedness documentation.

Phase 3: On-Site Inspection (2-5 Days)

• Opening meeting: Present audit scope and methodology to facility management.
• Facility inspection: Systematic walk-through of all areas — production, utilities, chemical storage, waste storage, ETP/STP, stack monitoring points, DG sets, fuel storage.
• Sampling and monitoring: Air quality sampling, water quality testing, noise level measurements, soil sampling (if warranted).
• Record verification: Cross-check documentary evidence against on-ground conditions. Verify monitoring equipment calibration, operator training, and emergency equipment readiness.
• Interviews: Discuss environmental management practices with EHS officers, plant managers, maintenance staff, waste handlers, and operators.
• Photographic documentation: Visual evidence of compliance, non-compliance, and areas for improvement.
• Closing meeting: Present preliminary findings and discuss major observations.

Phase 4: Reporting (2-3 Weeks)

• Analyse monitoring data and compare against regulatory standards.
• Classify findings as Non-Compliance (NC), Observation (OBS), or Best Practice (BP).
• Prepare comprehensive audit report with executive summary, detailed findings, monitoring data, and recommendations.
• Develop corrective action plan with priorities, timelines, and responsibilities.

Deliverables

A professional environmental audit produces the following deliverables:

1. Environmental Compliance Status Report

The primary deliverable — a comprehensive document that includes:

• Executive summary with overall compliance status (Compliant / Partially Compliant / Non-Compliant).
• Permit and authorisation status summary.
• Domain-wise findings (air, water, waste, noise, soil, chemicals, EHS).
• Monitoring data tables with comparison against regulatory standards.
• Photographic evidence of findings.
• Regulatory mapping — each finding linked to the specific legal requirement.

2. Non-Compliance Register

A structured register of all non-compliance findings, categorised by:

• Critical: Non-compliance that poses immediate environmental or health risk, or could result in regulatory action (shutdown, penalty).
• Major: Non-compliance with a significant regulation or permit condition that requires prompt corrective action.
• Minor: Non-compliance with administrative or documentation requirements, or deviations that do not pose immediate risk.
• Observations: Areas for improvement that are not strict non-compliances but represent best-practice gaps.

3. Environmental Monitoring Data Pack

Compiled monitoring data from the audit sampling programme:

• Air quality monitoring results (stack and ambient).
• Water quality analysis results (effluent, drinking water, groundwater).
• Noise level measurements with zone classification.
• Soil and groundwater sampling results (if conducted).
• Laboratory certificates from NABL-accredited laboratories.

4. Environmental Impact Summary

A quantitative summary of the facility's environmental impact:

• Total air pollutant load (tonnes/year of PM, SO2, NOx).
• Effluent discharge volume and pollutant load.
• Hazardous and non-hazardous waste generation quantities.
• GHG emissions (Scope 1 and Scope 2).
• Comparison with previous audit data to show trends.

Corrective Action Plans

The corrective action plan transforms audit findings into a managed improvement programme:

Structure

Each corrective action entry includes:

• Finding reference: Link to the specific non-compliance or observation in the audit report.
• Root cause: Why the non-compliance occurred (procedure gap, equipment failure, training deficiency, resource constraint).
• Corrective action: Specific action to be taken to address the finding.
• Preventive action: Systemic change to prevent recurrence.
• Responsible person: Named individual accountable for implementation.
• Timeline: Target completion date — critical items within 30 days, major items within 90 days, minor items within 180 days.
• Resources required: Budget, equipment, external expertise needed.
• Verification: How completion will be verified (evidence, re-monitoring, re-inspection).

Priority Classification

• Immediate (0-30 days): Critical non-compliances posing environmental or health risk, or likely to attract regulatory action.
• Short-term (30-90 days): Major non-compliances requiring equipment upgrades, procedure changes, or training programmes.
• Medium-term (90-180 days): Minor non-compliances and improvement opportunities requiring planning and budget allocation.
• Long-term (180+ days): Strategic improvements — technology upgrades, system implementation, infrastructure changes.

How Environmental Audits Feed into Green Audits and ISO 14001

Feeding into Green Audits

The environmental audit provides critical inputs to several domains of the green audit:

• Air quality and emissions domain: Stack emission data, ambient air quality monitoring, GHG inventory, and pollution control equipment effectiveness directly feed into the green audit's emissions scoring.
• Waste management domain: Hazardous waste quantification, segregation practices, disposal compliance, and recycling rates support the green audit's waste scoring.
• Water management domain: Effluent quality data, treatment effectiveness, and discharge compliance inform the green audit's water assessment.
• Compliance baseline: The environmental audit establishes the regulatory compliance baseline — the green audit then evaluates performance beyond minimum compliance.

Supporting ISO 14001 Implementation

For organisations implementing or maintaining an Environmental Management System (EMS) under ISO 14001, the environmental audit serves multiple functions:

• Initial environmental review (Clause 4.1): The audit identifies all environmental aspects, impacts, and regulatory obligations — foundational for EMS scoping.
• Legal register (Clause 6.1.3): The regulatory compliance matrix from the environmental audit forms the basis of the legal register required by ISO 14001.
• Operational controls (Clause 8.1): Audit findings guide the development of operational controls for significant environmental aspects.
• Performance evaluation (Clause 9.1): Monitoring data from the environmental audit provides baseline metrics for ongoing performance evaluation.
• Internal audit input (Clause 9.2): Environmental audit methodology and checklists inform the ISO 14001 internal audit programme.
• Management review (Clause 9.3): Environmental audit findings are key inputs to the management review process.

An environmental audit protects the organisation from regulatory risk today, while providing the compliance data that strengthens green audit scores and supports the broader journey towards ISO 14001 and sustainable operations.

Frequently Asked Questions

What is an environmental audit?

An environmental audit is a systematic assessment of a facility's compliance with environmental regulations and the effectiveness of its environmental management controls. It covers air emissions, water discharge, hazardous waste management, noise levels, soil contamination, chemical storage, and EHS practices. The audit produces a compliance status report with non-compliance findings and corrective action recommendations.

How is an environmental audit different from a green audit?

An environmental audit is primarily compliance-focused — it checks whether the facility meets applicable environmental laws and regulations (CPCB/SPCB norms, Consent to Operate conditions, Hazardous Waste Rules). A green audit is broader and performance-focused — it evaluates holistic environmental performance including energy, water, waste, biodiversity, procurement, and awareness, often producing a scored rating. Environmental audit findings feed into the emissions, waste, and compliance domains of a green audit.

What regulations does an environmental audit check?

In India, an environmental audit checks compliance with: Water (Prevention and Control of Pollution) Act, Air (Prevention and Control of Pollution) Act, Environment Protection Act, Hazardous and Other Wastes Rules, E-Waste Management Rules, Biomedical Waste Management Rules, Solid Waste Management Rules, Noise Pollution Rules, Consent to Operate conditions, and Environmental Clearance conditions where applicable.

How often should environmental audits be conducted?

For industrial facilities with Consent to Operate, annual environmental monitoring and periodic compliance audits are standard practice. For NAAC-affiliated educational institutions, at least once during the assessment period (every 5 years), ideally every 2-3 years. ISO 14001-certified organisations conduct internal environmental audits annually and are subject to external surveillance audits.

How does an environmental audit support ISO 14001?

An environmental audit provides the compliance evaluation and environmental performance data that ISO 14001 requires for its planning (Clause 6), operational control (Clause 8), and performance evaluation (Clause 9) requirements. For organisations implementing ISO 14001, the environmental audit serves as an initial review to identify regulatory obligations, aspects, and impacts — forming the foundation for the Environmental Management System (EMS).