4.9 Google
Corridor & right-of-way due diligence · Nationwide · ASTM E1527-21 compliant
Tell us the project route — the road, water main, or pipeline corridor and its right-of-way. We review the scope and send a custom quote within 1 hour, priced to the corridor length and the land uses along it.
Our environmental professionals run the regulatory database review, historic aerials, fire insurance maps, and FOIA requests across every property the corridor touches, then conduct field reconnaissance along the route.
You receive an ASTM E1527-21 corridor report that classifies each area as No Concern, Low, Medium, or High Risk. High Risk findings can move to a Preliminary Site Investigation (PSI) — the corridor equivalent of a Phase 2 ESA.
A PESA is the corridor version of a Phase 1 ESA. For a single parcel you want a Phase 1 ESA; for a project route that crosses many properties you want a PESA — and if it flags High Risk, the next step is a PSI.
"We were running up against some deadlines, and they jumped through hoops to get everything completed on time."
"The A3E team did a great job on our Phase 1 report. They were quick, thorough and professional."
"They were able to give me all of the information that I needed. Highly recommend A3 Environmental."
Compliant reports
Small business (WOSB)
Environmental consulting
Google Reviews
A Preliminary Environmental Site Assessment (PESA) is the same investigation as a Phase 1 ESA, except it is performed on a corridor of right-of-way (ROW) rather than a single commercial property. In practice, it is a long, narrow Phase 1 ESA: it examines the same kinds of environmental impacts across every property a project route touches, following the ASTM E1527-21 standard. PESAs are used by governments — State Departments of Transportation, counties, and municipalities — preparing infrastructure projects like road widening, water main installation, and pipeline routes that cross many parcels.
The difference between a PESA and a Phase 1 ESA is scope, not rigor. A Phase 1 ESA evaluates one commercial property and reports Recognized Environmental Conditions (RECs). A PESA evaluates a linear corridor and classifies each area along the route as No Concern, Low, Medium, or High Risk. That risk-tiered output is what an agency needs to plan a project that runs through dozens of different landowners and land uses at once — you cannot manage a ten-mile road project with a single-parcel report.
Governments commission PESAs for three practical reasons. First, worker safety: crews need to know where they may encounter contaminated soil or groundwater before they break ground. Second, project budgeting: identifying contaminated soil early lets an agency budget for proper removal and disposal instead of discovering it mid-construction. Third, containment: a PESA helps prevent spreading contamination along a pipeline or excavation. When a corridor area comes back High Risk, the next step is a Preliminary Site Investigation (PSI) — the corridor equivalent of a Phase 2 ESA — which uses subsurface sampling to confirm or rule out contamination.
Every A3 Environmental PESA begins with a regulatory database review at the federal, state, county, and municipal level along the full corridor, paired with historic aerial photographs, fire insurance maps, city directories, and FOIA requests to government officials. Our environmental professionals then conduct field reconnaissance along the route and deliver an ASTM E1527-21 corridor report with each area risk-classified and clear next-step recommendations. A3 Environmental performs PESAs in all 50 states — backed by deep Midwest roots and a 4.9★ Google rating since 2015 — completing roughly 50 Phase 1-class assessments a month nationwide.
