Phase I Environmental Site Assessments in Commercial Transactions

A Phase I Environmental Site Assessment exists to protect a buyer from liability it did not create. Under CERCLA — the federal Superfund statute at 42 U.S.C. § 9601 and following — an owner can be held strictly liable for cleaning up contamination, jointly and severally with others, without any fault. The statutory escape routes all depend on one thing: that the buyer conducted All Appropriate Inquiries into prior uses before acquiring the property. A Phase I documents that inquiry. Order it after closing and the defense is gone.

The liability the report is answering

CERCLA reaches current owners and operators, past owners and operators at the time of disposal, generators and transporters. A buyer of a former dry cleaner, machine shop, filling station or plating operation steps into the current-owner category on the day of closing, whether or not it spilled anything.

Three defenses matter to a purchaser. The innocent landowner defense covers a buyer who did not know and had no reason to know of contamination. The bona fide prospective purchaser provision allows a buyer to acquire a property knowing it is contaminated, provided disposal occurred before acquisition and the buyer meets continuing obligations. The contiguous property owner provision covers an owner contaminated by migration from a neighbouring site.

Every one is conditioned on All Appropriate Inquiries before acquisition. EPA's All Appropriate Inquiries pages set out the rule and identify the ASTM practice that satisfies it. Because the standard is periodically revised and EPA updates the rule to reference the current version, confirm the applicable version there rather than trusting a version letter from a secondary source. As of mid-2026 that arrangement still governs, so the operative practice can change without CERCLA changing.

The federal rule is not the whole picture

CERCLA and All Appropriate Inquiries are federal. States run parallel systems that can impose duties a federal analysis would never surface: their own cleanup statutes and liability schemes, and voluntary cleanup or brownfield programs offering closure letters or covenants not to sue.

A smaller group operate transfer-triggered statutes, requiring investigation, disclosure or approval before certain industrial properties may change hands. New Jersey's is the best-known example, and where such a statute applies it can control the closing timetable outright, whether or not the buyer wants a federal defense.

Inside the scope, outside the scope, and Phase II

A Phase I is deliberately non-intrusive: nothing is drilled, dug or sampled. The environmental professional reviews records and historical sources, walks the site, interviews people who know it, and reports whether any recognized environmental conditions — RECs — are present. A REC indicates a release or a likely release, not proof of one.

The distinction has consequences. A Phase I finding no RECs is not a certificate that the property is clean; it reports that the professional found nothing indicating a release using a defined, non-invasive methodology. A REC is not a finding of contamination either — it triggers the decision whether to sample. The report must be prepared or supervised by an environmental professional as EPA defines that term, and the declaration that professional signs is part of what makes the report count.

Timing and shelf life

The inquiry must be completed before acquisition. That is the fixed point around which everything else is scheduled, and the requirement most often missed in a fast deal.

The standard also gives the report a shelf life measured in months rather than years, in two tiers. Certain components — interviews, the lien and use-limitation search, the government records review, the site reconnaissance, and the professional's declaration — must be updated if completed more than a set period before acquisition. The report as a whole goes stale after a longer interval, after which a new assessment is needed.

In practice, transactional lawyers work with 180 days for the components and one year for the report overall. Those are the market's figures, but the operative numbers come from the current ASTM practice and the EPA rule, so confirm them against EPA's All Appropriate Inquiries page for the deal in front of you.

Watch out: A Phase I ordered after closing does not retroactively create a defense, however thorough it is. The same problem arises with a foreclosure, a deed in lieu, a contribution of property to a joint venture, or an acquisition of an entity that owns real estate — each is an acquisition point needing its own analysis. Structuring questions of that kind sit alongside those covered in our piece on joint venture contributions, control and exit.

Ordering one inside a due-diligence period

1. Build the time into the contract. The due-diligence period must fit a Phase I and, if a REC appears, a Phase II. Negotiate an extension right tied to that contingency.
2. Get access rights in writing. The consultant must walk the site and, for a Phase II, drill. A tenant in possession may refuse, so bind the seller to deliver access.
3. Define scope and addressees before engagement. Name every party who will need to rely — buyer, lender, equity partner, guarantor. Adding names later costs money.
4. Add the non-scope items you need. Asbestos and lead surveys for an older building, radon in a residential conversion, vapour intrusion near a solvent user.
5. Read the findings, not the conclusion page. The historical use and adjoining-property sections usually carry more risk information than the summary.
6. Decide on Phase II inside the contingency window. Sampling, a holdback, an indemnity, or walking away all have to be settled before it expires.
7. Confirm currency at closing. If the deal slips, check whether components need updating before the acquisition date.

Reliance deserves emphasis. A report addressed to the seller cannot simply be picked up by the next party; reliance flows from the engagement and an express reliance letter, and a lender will insist on being named. The lender's collateral position on the personal-property side raises the separate questions our explainer on UCC security interests and perfection addresses.

Keeping the defense after closing

All Appropriate Inquiries opens the door; continuing obligations keep it open. A bona fide prospective purchaser must take reasonable steps as to hazardous substances found, cooperate with agencies and provide access, comply with land-use restrictions and institutional controls, not impede a response action, and answer information requests. A buyer that walks away from those duties can lose the protection it paid for, which is why the file matters as much as the report.

• The complete Phase I report, with appendices, historical sources and the signed declaration.
• Evidence of the qualifications of the environmental professional who supervised the work.
• The engagement letter and any reliance letters, showing who could rely and on what terms.
• The buyer's own responses to the inquiries the rule assigns to the purchaser, including specialized knowledge and how the price compared with the value of an uncontaminated property.
• Any Phase II reports, laboratory data and consultant recommendations.
• Records of reasonable steps taken after closing and of compliance with recorded use limitations.
• Correspondence with state agencies and any voluntary cleanup or no-further-action documentation.

Environmental risk is not the only site condition worth a written record. Flood exposure and boundary encroachments carry their own diligence trails — see our pieces on flood zone disclosure and elevation and on adverse possession and prescriptive rights. Programs run through HUD and cleanup grants from the EPA can carry environmental conditions of their own where public funding is involved.

Common questions

The seller already has a Phase I. Can I just use theirs?

Not without permission. A report belongs to the party that commissioned it, and the consultant's duty runs to the named addressees. To use a seller's report you generally need a reliance letter from the consultant naming you, and often your lender too. Even then, check the completion date against the shelf-life rules and whether components need updating before your acquisition date.

We closed last month and only now realise nothing was ordered. Is anything salvageable?

The defenses that depend on pre-acquisition inquiry are generally not recoverable, because the timing requirement is the whole point. What can still be done is worth doing: an assessment now establishes the condition of the property, shows whether a state voluntary cleanup program is available, supports contribution or indemnity claims against other responsible parties, and gives any future buyer a factual baseline.

If the report finds no recognized environmental conditions, is the property clean?

No. A Phase I is a records and observation exercise with no sampling, so a clean report means the professional found nothing indicating a release using that methodology. Contamination can exist below ground with no surface evidence and no documentary trail, particularly where historical records are sparse. The report also excludes asbestos, lead, radon and mould unless separately commissioned.

Does a lender's environmental requirement replace what the buyer needs?

Usually not exactly. A lender orders a report to protect its collateral and its own exposure, and its scope may be narrower or differently focused than what a buyer needs for a statutory defense. The addressee question also differs. Treat the lender's requirement as a floor, confirm the scope satisfies All Appropriate Inquiries, and make sure the buying entity is named as an intended user.

Sequencing the environmental work in a deal

1. Screen the property before you sign. Prior industrial or fuel-handling use should shape the contingency period you negotiate.
2. Engage the environmental professional yourself. Name every intended user in the engagement letter, including the lender and any equity partner.
3. Check the state layer in parallel. Identify whether a transfer-triggered statute or state cleanup program applies before the federal analysis is finished.
4. Treat a REC as a decision point, not a red light. Price the Phase II and possible remediation, then decide whether to sample, adjust price, take an indemnity, or walk.
5. Confirm currency immediately before closing. The shelf-life rules run to the acquisition date, not the report date.
6. Open the continuing-obligations file on day one. Reasonable steps, agency cooperation and compliance with land-use controls are ongoing, and evidence is easiest to gather as it happens.