Preliminary Site Investigations (PSI)

A PSI / environmental due diligence is essentially the first step in investigating risk associated with contamination under Australia’s national environmental guidelines.

We service the whole of Australia in providing PSIs for a wide range of industries and developments from our offices located in:

Not every property requires a Preliminary Site Investigation (PSI), but yours might. The purpose of a PSI is to assess the potential for contamination of a site.

Typical triggers of a PSI include:

Preliminary Site Investigations (PSI) & Desktop Environmental Due Diligence (EDD)

Our Preliminary Site Investigations (PSI) and desktop Environmental Due Diligence (EDD) services help enterprise clients, government agencies, and institutional investors identify contamination risk early, before a transaction, development, excavation, or land use change proceeds. A PSI is the first step in assessing the potential for onsite and offsite contamination and its risk to human health and the environment, based on a structured review of historical land use, available records, site setting, and environmental pathways. Depending on your requirements, iEnvironmental Australia can deliver a desktop-only PSI/EDD, or include limited sampling for greater certainty, helping you avoid unexpected liability, manage negotiations, and ensure reports meet regulator and financier expectations.

CEnvP CS Specialists, Regulator-Ready Reporting, and Confidential Service for Major Decisions

When millions are at stake, environmental risk cannot be treated as a checkbox. Our contamination and due diligence work is designed for high-stakes decisions where credibility, defensibility, and clear next steps matter. iEnvi’s Certified Environmental Practitioners Site Contamination Specialists (CEnvP CS) design and review PSI and due diligence scopes to support mergers and acquisitions (M&A), property acquisitions and disposals, planning and development approvals, baseline contamination assessments prior to lease or sale, and finance using property as collateral. You receive enterprise-grade reporting that supports decision-making, clarifies potential contaminants of concern and exposure pathways, and recommends the most cost-effective next stage (if required), from Detailed Site Investigation (DSI) through risk assessment and remediation planning, delivered with discretion and an institutional client focus.

Your Preliminary Site Investigation will begin with a review of your property’s history. This is completed by the investigator off-site using historical government databases, historical aerial photographs, geological, groundwater, reports and other documents, planning drawings, and other available records. It is often referred to as a “desktop study”.

In addition, you can choose to have a site inspection conducted, where the investigator may need to ask some questions of everyone concerned, and walkover the property to make observations – this will take longer for industrial properties. Sometimes soil samples are taken during the PSI. This will depend on the nature of the reason you require a PSI, and the potential for contamination for the property. It is more cost effective to include soil sampling during the PSI, and this further reduces the risk substantially and increases certainty for potential purchasers.

Then you get your report. If your site has potential for contamination, the report will explain what the chemical contaminants are and where, and how this may be a concern for the current and future planned use of the property. The report will also explain what steps need to be taken next to investigate further. This is simply a preliminary report, but it is very detailed.

It is possible to “pass” a PSI, and have a property cleared as having a low risk of contamination and low contamination risk to people and the environment. Sometimes further investigation is not required.

The objective of the PSIs to help determine the potential for risk to human health and the environment from both current and historical, onsite and offsite land contamination.