Navigating the PA Chapter 102 NPDES (National Pollutant Discharge Elimination System) permitting process for your construction projects involves more than just managing sediment and runoff. One of the most critical hurdles in the Notice of Intent (NOI) is the requirement to identify pre-existing soil contamination.
Specifically, the Notice of Intent (NOI) asks the Applicant to confirm that “soils in the area of the earth disturbance are not contaminated.” This is an important question because construction inherently involves moving, stockpiling and spreading soil. If impacted soil exists, earthwork can expose crews to hazardous materials and allow stormwater runoff to facilitate the migration of contaminants into downstream waterways.
While it’s impossible to confirm a site is 100% “clean” without sampling every cubic inch, a thorough review of current and historical operations is essential to identifying likely risks. By using historic resources such as USGS topographic maps, Penn State’s Penn Pilot for historic aerials dating back to 1937 and even historic Google Street View, we can look back at the last 50 years of a property's history. Understanding a site's history helps us determine whether soil sampling should be performed. Certain historical land uses are immediate red flags that can trigger a soil investigation. Here are some common culprits:
- Gas Stations
This is the most obvious risk. Underground Storage Tanks (USTs) for gasoline and diesel are notorious for leaking over time. Even if a tank was removed decades ago, older, unregulated tanks often leave behind a plume of petroleum hydrocarbons (BTEX) that can persist in soil and groundwater.
Historic Google Street View (2012) of a former gas station that has since been demolished.
- Dry Cleaners
Dry cleaners are high-risk due to solvents like PCE (Perchloroethylene) and TCE (Trichloroethylene). These chemicals are "dense non-aqueous phase liquids" (DNAPLs), meaning they are heavier than water, sink through the water table, and spread easily. In the mid-20th century, the environmental impact of these solvents wasn't fully understood. Spills and "backdoor" disposals were common, and because these chemicals are relatively stable, they linger for decades.
- Historic Farms
When a farm is used solely for growing row crops, residual pesticide concentration levels are often relatively low. But other areas of historic farm properties could be significant concerns.
- Orchards: From the late 1800s until the 1950s, lead arsenate was the gold standard for controlling the codling moth in fruit orchards. It was used because it was highly effective and adhered well to the fruit. However, lead and arsenic don’t break down and can remain in the soil for decades.
- Unregulated Tanks: Farms often operated with small, unregulated diesel or gasoline tanks to fuel tractors and machinery. Without the oversight required for commercial gas stations, leaks often went unnoticed and unreported for years. Because these tanks are often underground and poorly documented, they can get “lost" in time. When land is sold or passed to heirs, these forgotten tanks become a hidden environmental liability, left to corrode and leak until they are inevitably discovered during site development.
- Farm Dumps: Historic farms often had designated areas for solid waste. These "junk" piles often included used motor oil, lead-acid batteries and broken vehicle parts, all of which can leach heavy metals and oils into the surrounding soil.
Historic aerials from Google showing a farm property with a farm dump.
- Golf Courses
Maintaining those pristine greens requires heavy chemical intervention. Impacts are often concentrated on greens, fairways, and tees, which receive the highest application of pesticides. Historically, these pesticides contained heavy metals such as lead and arsenic.
Historic USGS Topographic Map (1954) identifying a historic golf course.
If contaminated soils are identified on-site, a standard General NPDES Permit could be elevated to an Individual NPDES Permit. Individual permits are more costly, have longer review timelines and require more stringent erosion, sediment and stormwater controls.
Furthermore, managing impacted soil (identifying the extent of the plume, preparing a remediation plan, obtaining PADEP approvals and disposing of material at an approved facility) requires substantial time and money.
In the world of Chapter 102 permitting, ignorance is not bliss; it is an expensive delay. Performing due diligence during the design phase allows you to address soil concerns before the first excavator arrives. By identifying these historical "red flags" early, you can develop a strategy that keeps your project compliant, your budget intact and your timeline on track.
