Phase 1 Preliminary Site Investigations (PSI)

At Atlas Engineering and Technology Group, our Phase 1 Preliminary Site Investigations (PSI) give developers, landowners, financiers, and project teams a clear, early understanding of potential contamination risks affecting a property.

What Is a Phase 1 PSI?

A Phase 1 Preliminary Site Investigation is a primarily desktop and qualitative assessment designed to identify whether past or present land uses may have caused contamination, and whether further investigation is warranted.

It answers a fundamental question: Is contamination likely to be present on this site, and could it pose a risk to human health or the environment?

A PSI does not typically involve extensive soil or groundwater sampling. Instead, it draws on historical records, site observations, and regulatory information to develop a preliminary conceptual site model and identify potential areas of environmental concern.

Our investigations are carried out in accordance with the NSW EPA guidelines and the National Environment Protection (Assessment of Site Contamination) Measure (NEPM).

When Do You Need a PSI?

A Phase 1 PSI is commonly required or recommended for:

  • Property transactions: it informs purchasers, vendors, and financiers of potential contamination liabilities during due diligence.
  • Development applications: it supports planning approvals, particularly under State Environmental Planning Policy (Resilience and Hazards) 2021 (formerly SEPP 55).
  • Change of land use: where land is being rezoned for more sensitive uses such as residential, childcare, or open space.
  • Regulatory compliance: it addresses council, EPA, or planning authority requirements.
  • Risk management: it provides landowners and lenders with an informed understanding of environmental risk.

What Our PSI Includes

1. Site History Review

We compile and review the historical land use of the site using:

  • Historical aerial photographs.
  • Land title and ownership records.
  • Council records, development approvals, and building plans.
  • Historical business and trade directories.
  • Previous environmental reports, where available.

2. Regulatory & Database Searches

We search relevant regulatory records, that includes:

  • EPA contaminated land records and notices.
  • WorkCover / SafeWork dangerous goods records.
  • Licensed premises and trade waste records.
  • Groundwater bore registers.

3. Site Walkover Inspection

Our environmental scientists conduct a visual inspection of the site and surrounding area to identify physical evidence of potential contamination, including:

  • Staining, odours, or stressed vegetation.
  • Storage of chemicals, fuels, or hazardous materials.
  • Above- and below-ground storage tanks.
  • Fill material, waste, or imported soils.
  • Evidence of asbestos-containing materials.

4. Geological & Hydrogeological Setting

We review regional geology, soil types, groundwater conditions, and nearby sensitive receptors to understand contaminant migration potential.

5. Conceptual Site Model (CSM)

We develop a preliminary conceptual site model identifying potential sources of contamination, exposure pathways, and receptors.

6. Reporting & Recommendations

We deliver a clear, defensible PSI report that:

  • Identifies potential areas of environmental concern (PAECs).
  • Assesses the likelihood of contamination.
  • Provides a professional opinion on site suitability.
  • Recommends whether a Phase 2 Detailed Site Investigation (DSI) is required.

Possible Outcomes of a PSI

A Phase 1 PSI typically concludes with one of the following findings:

  • No further investigation required: the site is considered suitable for the proposed use, with low contamination risk.
  • Further investigation recommended: potential contamination concerns warrant a Phase 2 Detailed Site Investigation involving intrusive sampling and analysis.
  • Specific concerns identified: targeted assessment or management measures are recommended.

Why Choose Atlas Engineering and Technology Group?

  • Experienced Environmental Professionals Our team applies rigorous, evidence-based methodology aligned with NSW EPA and NEPM requirements.
  • Integrated Expertise As a multidisciplinary group offering Geotechnical, Environmental, and Testing services, we provide seamless support if further investigation is required.
  • Local Knowledge Sydney-based, with a deep understanding of NSW planning frameworks and regional site conditions.
  • Defensible Reporting Reports prepared to withstand scrutiny from councils, the EPA, and other stakeholders.
  • Responsive Service We work to your transaction and project timelines to keep your plans moving.

Related Services

  • Phase 2 Detailed Site Investigations (DSI)
  • Contaminated Land Remediation
  • Soil & Groundwater Sampling
  • Hazardous Materials Surveys
  • Waste Classification

Get in Touch

Considering a property purchase, development, or change of land use? Start with a Phase 1 Preliminary Site Investigation. Contact the environmental team at Atlas Engineering and Technology Group today to discuss your project and request a quote.