Environmental due diligence has always been a critical part of commercial real estate transactions, but in 2026, lenders are applying more scrutiny than ever before. Updated ASTM standards, emerging contaminants, and increased regulatory enforcement have changed what banks, SBA lenders, and private equity firms consider acceptable environmental risk.

A Phase 1 Environmental Site Assessment (ESA) is no longer a simple box to check. It is a risk evaluation tool — and lenders are paying close attention to specific red flags that can delay financing, require additional investigation, or even derail a transaction entirely.

This guide explains the new red flags lenders are watching for in 2026, how they impact buyers and sellers, and what steps you can take to avoid costly surprises.

Why Phase 1 ESA Requirements Are Changing in 2026

Several major trends are reshaping environmental due diligence:

• ASTM E1527-21 is fully adopted, with stricter requirements for historical research and site characterization.
• PFAS and other emerging contaminants are now considered potential Recognized Environmental Conditions (RECs).
• Vapor intrusion concerns are increasing across industrial and commercial properties.
• Insurance carriers are requiring more detailed environmental documentation.
• Regulators are expanding enforcement, especially around hazardous materials storage and waste management.
• Lenders are more risk-averse due to market volatility and redevelopment pressures.

As a result, Phase 1 ESAs in 2026 are more detailed, more conservative, and more likely to identify issues that require further investigation.

Top Red Flags Lenders Are Watching For in 2026

Below are the most significant issues that lenders consider high-risk — and that frequently trigger Phase 2 investigations or financing delays.

1. PFAS Risk Indicators

PFAS (per- and polyfluoroalkyl substances) are now one of the most scrutinized environmental risks in real estate.

PFAS red flags include:

• Historical industrial operations
• Firefighting foam use
• Manufacturing or plating facilities
• Landfills or waste disposal sites
• Food processing or packaging operations
• Proximity to airports or military sites

Even if PFAS is not sampled during a Phase 1, lenders may require additional investigation if risk indicators are present.

2. Vapor Intrusion Concerns

Vapor intrusion has become a major focus due to updated EPA guidance.

Red flags include:

• Historical use of solvents
• Dry cleaners
• Auto repair shops
• Manufacturing operations
• Adjacent contaminated properties
• Known groundwater contamination nearby

Lenders often require vapor intrusion screening or Phase 2 sampling when these conditions exist.

3. Incomplete or Outdated Hazardous Materials Documentation

Lenders now expect facilities to maintain:

• Hazardous materials inventories
• SDS documentation
• HMIS
• MAQ calculations
• Fire code compliance records

If documentation is missing or outdated, lenders may consider the property higher risk — especially for industrial or warehouse operations.

4. Historical RECs That Were Never Closed

Old contamination issues that were never formally resolved are a major red flag.

Examples include:

• Underground storage tanks removed without documentation
• Historical spills with no closure letter
• Past violations with no follow-up records
• Old environmental reports with unresolved recommendations

Lenders may require updated investigations to confirm conditions.

5. Waste Management Issues

Improper waste handling is a growing concern.

Red flags include:

• Unknown waste streams
• Improper labeling
• Lack of hazardous waste determinations
• Missing inspection logs
• Poor storage conditions
• Evidence of spills or staining

These issues can indicate broader compliance problems.

6. Fire Code Compliance Gaps

Fire departments are enforcing hazardous materials storage more aggressively, and lenders are paying attention.

Red flags include:

• MAQ exceedances
• Improper flammable storage
• Missing fire barriers
• Lack of ventilation
• Outdated HMIS
• Missing SDS sheets

Properties with fire code issues may face operational restrictions or costly upgrades.

7. Adjacent Property Risks

Lenders now consider off-site risks more seriously.

Examples:

• Neighboring dry cleaners
• Former gas stations
• Industrial operations
• Landfills
• Rail corridors
• Known contaminated sites

Even if your property is clean, nearby contamination can impact financing.

8. Poor Site Housekeeping

This is one of the simplest — yet most overlooked — red flags.

Indicators include:

• Staining on floors or soil
• Leaking containers
• Improper chemical storage
• Waste accumulation
• Lack of secondary containment

Poor housekeeping suggests broader compliance issues and increases lender concern.

9. Missing or Incomplete Historical Records

ASTM E1527-21 requires more thorough historical research.

Red flags include:

• Gaps in aerial photos
• Missing city directory records
• Incomplete fire insurance maps
• Lack of historical permits
• Unclear past operations

Lenders may require additional investigation if historical use cannot be verified.

10. Evidence of Past Industrial Use Without Documentation

Properties that “look industrial” but lack records are high-risk.

Examples:

• Old floor drains
• Stained concrete
• Vent stacks
• Abandoned equipment
• Unknown piping
• Former loading docks

These features often indicate past operations that may have caused contamination.

How These Red Flags Affect Buyers and Sellers

For Buyers

• Delayed financing
• Additional Phase 2 sampling
• Higher insurance requirements
• Renegotiated purchase terms
• Potential deal termination

For Sellers

• Lower property value
• Required corrective actions
• Longer time on market
• More buyer demands
• Increased scrutiny of operations

A clean, well-documented Phase 1 ESA reduces risk for both parties.

How to Avoid Phase 1 ESA Problems in 2026

1. Conduct a Pre-ESA Environmental Review

Identify issues before the lender does.

2. Update Hazardous Materials Documentation

HMIS, SDS, MAQs, and inventories must be current.

3. Improve Housekeeping and Storage

Correct small issues before inspections.

4. Gather Historical Records

Fill gaps in aerials, directories, and permits.

5. Address Old RECs

Resolve past issues and obtain closure letters.

6. Work with an Experienced ESA Consultant

A thorough Phase 1 ESA prevents surprises.

Caltha LLP specializes in identifying and resolving environmental risks before they impact financing.

Conclusion

Phase 1 ESAs in 2026 are more detailed, more conservative, and more likely to identify issues that lenders consider high-risk. Understanding these red flags — and addressing them proactively — can prevent costly delays, additional investigations, or failed transactions.

Whether you are buying, selling, or refinancing, a high-quality Phase 1 ESA is essential for protecting your investment and ensuring a smooth closing.

Request an On-line Quote For A Phase 1 ESA

If you need a Phase 1 ESA, pre-transaction environmental review, or help resolving red flags before a lender identifies them, Caltha LLP can assist. Contact us to schedule an assessment or request a quote.