Landfill Gas Risk Assessment
During the decomposition of waste within landfill environments, both gaseous emissions and liquid byproducts, commonly referred to as landfill gas and leachate, are generated as part of the natural biological and chemical breakdown processes. While engineered containment and management systems are typically implemented to mitigate these emissions, there remains an inherent risk that these substances may migrate beyond the landfill boundaries. If uncontrolled, such releases have the potential to adversely affect surrounding ecosystems, degrade soil and water quality, and pose risks to human health through air or groundwater contamination.
Why is a Landfill Gas Risk Assessment required?
For property owners, prospective buyers, developers, and construction professionals, understanding the implications of landfill buffer zones is essential. Developments located in proximity to former landfills may be subject to additional planning requirements due to the potential for subsurface gas migration. Gases such as methane and carbon dioxide can accumulate in enclosed structures, posing significant health and safety risks, including the potential for fire or explosion. Regulatory authorities may require environmental assessments, gas mitigation measures, or design modifications prior to granting planning approval. Early consideration of these factors can help avoid compliance issues, mitigate safety concerns, and reduce delays or unforeseen costs during project delivery.
In accordance with the Victorian Environment Protection Authority’s guidance document, Best Practice Environmental Management: Siting, Design, Operation and Rehabilitation of Landfills (Landfill BEPM), all buildings and structures located within 500 metres of a closed municipal (putrescible) landfill are considered to be within the recommended landfill buffer zone. Development within this zone is subject to careful scrutiny, as it may facilitate pathways for landfill gas migration that could impact both the built environment and human health.
Environmental & Health Risks
Landfill gas, particularly methane and carbon dioxide, can migrate through soil and accumulate in buildings, creating fire, explosion, or health hazards for nearby residents and workers.
Regulatory Non-Compliance
Landfill gas risk assessments are mandated for developments within buffer zones of former landfills. Non-compliance can lead to planning delays, permit rejections, or enforcement actions under environmental protection legislation.
Financial and Liability Risks
Failure to assess or manage landfill gas can result in costly retrofitting, remediation expenses, and legal liability—potentially affecting development approvals, resale value, and project feasibility.
Assessing and managing landfill gas risks is a critical and responsible step for landowners, developers, and businesses undertaking new developments or land use changes near former landfill sites.
Safety First – Lessons from Real Incidents
For Landfill Gas Risk Assesssment (LFGRA)
Landfill gas migration is not without risk. A real-world incident in Cranbourne, Victoria, investigated by the Victorian Ombudsman, highlights the critical importance of undertaking thorough Landfill Gas Risk Assessments (LFGRAs). In this case, residential properties were developed within close proximity to a closed landfill without adequate gas risk evaluation. Methane levels were later detected at dangerous concentrations, posing a serious risk of explosion. While no injuries occurred, the incident underscores the potential dangers when proper assessment and planning are overlooked.
At Terralis, we use this and other real-world examples to inform our safety-first approach and ensure every LFGRA is conducted with precision, regulatory compliance, and community safety in mind.
Our Comprehensive Services
Terralis offers a comprehensive range of services to support safe, compliant, and effective Landfill Gas Risk Assessments (LFGRAs). Our services include:
Landfill Buffer Screening
We assess whether a site falls within a landfill buffer zone and determine the need for landfill gas risk assessment in accordance with EPA and planning guidelines.
Preliminary Site Investigation (PSI)
We undertake background reviews, site inspections, and soil gas screening to evaluate the potential for landfill gas migration before development proceeds.
Soil Gas Monitoring
We install and monitor soil gas bores to collect data on landfill gas concentrations (methane, carbon dioxide, oxygen), helping to assess potential risks to health and property.
Risk Assessment & Modelling
Our specialists evaluate gas migration pathways, building vulnerabilities, and gas concentrations to model risk levels and inform mitigation decisions.
Gas Mitigation Design
Where required, we design and specify gas barriers, venting systems, and sub-floor ventilation to safely manage and control landfill gas migration on development sites.
Regulatory Reporting & Planning Support
We prepare detailed reports and technical documentation to support planning applications, ensuring compliance with EPA Victoria, Council, and planning scheme requirements.
Tailored Solutions for Every Site
Commitment to Safety and Compliance
Terralis prioritises the highest levels of occupational and environmental safety in all landfill gas risk assessment works. Our approach aligns with state and federal regulatory frameworks, ensuring full compliance with EPA Victoria’s Best Practice Environmental Management (Landfill BEPM) guidelines, the NEPM (Assessment of Site Contamination), and relevant Australian Standards, including AS 4482.1 and AS/NZS 3580.10.1. We stay up to date with legislative changes to ensure that all assessments reflect current best practice. Our team is licensed, qualified, and experienced in conducting LFGRAs that are robust, defensible, and tailored to support safe development within or near landfill buffer zones.
