Closing the Gap at Bulk Terminals: How Smarter, Risk-Based Oversight Drives Legacy Releases to Closure

Terminal Series – Article 6

Contributed by Trey Hess P.E., Principal, PPM Consultants

Legacy impacts at bulk liquid terminals don’t persist because teams aren’t trying—they persist because effort isn’t always aimed at the actual exposure pathways that matter today. Around racks, manifolds, valve pits, sumps, and secondary containment, it’s common to see long-running “monitor forever” items, recurring stormwater sheens, or stained concrete that never gets resolved.

A terminals-first, risk-based approach changes that. By eliminating real exposure pathways, documenting multiple lines of evidence, and applying simple, durable controls, terminals can close lingering issues faster—without compromising protection or consuming operating bandwidth.

From Compliance Checklists to Exposure-First Thinking

Routine inspections, samples, and plan updates are necessary but not sufficient. Closure requires a shift in mindset: threats first, numbers second.

Start by asking:

• Who could be exposed?
• How and when could exposure occur?

In most terminal scenarios, the plausible pathways are straightforward: free product (where present), worker contact during maintenance, indoor air near shops and warehouses, and off-site migration via utilities or stormwater outfalls.

Address consequences in order of significance, then determine what data is actually needed to confirm protection. This prevents teams from slipping into endless rounds of low-level sampling that add cost but change nothing on the ground.

Key shift:
“Is exposure plausible?” comes before “Do we need one more round of low numbers?”
When exposure is controlled and evidence converges, closure becomes both defensible and efficient. The Risk Evaluation Procedures of the Mississippi Department of Environmental Quality (MDEQ) include a risk-based corrective action approach that involves the elimination of exposure pathways through institutional and engineering controls.  Most states allow for similar risk-based approaches like this.

A Simple, Terminal-Focused Risk Framework

At each potential source area, use the same three questions:

1. What’s the plausible exposure?

Typical pathways include:

• Worker contact
• Indoor air near enclosed spaces
• Off-site migration through utilities or groundwater
• Stormwater discharge during rain events

2. What evidence do we have today?

Sized-to-risk evidence might include:

• Field screening
• Targeted soil borings
• Groundwater gauging and trend review
• Soil gas or indoor air screening in key buildings
• Stormwater visual/first-flush observations
• Photo logs

3. What control locks it down?

Controls range from:

• Coatings, liners, and joint sealing
• Drain isolation valves and filtration/OWS in dewatering
• No-dig notes, utility bedding isolation steps
• Simple inspection cadences & triggers for re-check

When multiple lines of evidence (not one lab result) point to low exposure + stable or improving conditions, you have a credible path to closure.  Statistical trend analysis like the Mann-Kendall statistical method is one approach we have used to “demonstrate to the satisfaction of MDEQ that contamination is not expanding or migrating off-site.”

Map First, Then Act: Build a Terminal Exposure Map

Before writing work orders or updating plans, create a shared map set (11×17 and 8.5×11) showing:

• Racks & trenches: drainage direction, low points, enclosed spaces
• Manifold pads & valve pits: stains, cracks, nearby utilities
• Secondary containment & ringwalls: joints, penetrations, dewatering points
• Stormwater outfalls: first-flush pathways, drains with covers/valves
• Shops/warehouses: proximity to subsurface concerns for indoor air screening

Add QR links in SPCC/SWPPP and FRP job aids so crews always have the current version.

Controls That Actually Work in the Field

Containment & pavements that stay clean

Coatings, liners, and sealed joints prevent storm events from mobilizing residues. Where bare concrete remains, set realistic inspection intervals—concrete isn’t leak-proof, it’s a managed surface.

Drain isolation and dewatering crews will actually follow

Label drain valves, stage covers at the point of use, and issue a one-page SOP covering:

• Visual checks
• Quick meter checks where required
• Simple filtration/OWS if sheen recurs
• A brief photo-log before and after discharge

Vapor & indoor air checks

Screen shops or enclosed spaces near racks/manifolds using a simple protocol. Most concerns resolve with basic ventilation, housekeeping, and a clear re-check trigger.

Institutional controls that survive turnover

Mark no-dig zones and hot-work sensitivities directly on the operating map and in the work-order system. If utilities could convey impacts, specify simple bedding isolation steps.

One-page documentation

Each area gets a single risk-register page:

• Exposure hypothesis
• Lines of evidence
• Controls
• Owner
• Review cadence

Attach these to SPCC/FRP annexes and the compliance calendar.

A Decision Structure That Moves Toward Closure

A three-tier structure keeps teams aligned:

Tier 1 – Screen

Use desktop review, field observations, limited screening, and photo logs to determine if exposure is plausible.

Tier 2 – Target

If needed, collect targeted borings or groundwater, stormwater first-flush checks, or soil gas/indoor air samples. Evaluate trends, not stand-alone numbers.

Tier 3 – Close

Document converging evidence, record controls, set triggers for re-check, and close the item with sign-offs.

At each tier, prepare a 1–2 page decision memo—enough for auditors, regulators, or buyers to follow the thread without a 200-page report.

Build Closure Into SPCC, Stormwater, FRP, and MOC

A risk-based approach should live inside your existing programs:

• SPCC: integrate coatings, joint sealing, and dewatering SOPs; align isolation/shutdown steps.
• Stormwater: ensure representative outfalls, first-flush considerations, and photo-logged inspections match actual operations.
• FRP: where legacy residues affect booming/drain control strategy, document staging notes and controls.
• MOC: any modification—new arm, resurfacing, drainage shift—triggers a quick exposure screen and map/SOP update.

People, Cadence, and Culture: How It Sticks

Make closure a rhythm, not a one-off project:

• Assign owners for each risk register and control.
• Conduct quarterly light-lift reviews with consistent photo points.
• Perform one annual functional drill (e.g., drain isolation + dewatering SOP).
• Maintain a single corrective-action tracker with close-out photos.
• Provide new personnel with a one-hour onboarding to maps, registers, and SOPs.

Two Quick Examples

Rack trench & first-flush issue—closed cleanly

After intermittent stormwater sheens at Outfall 003, an exposure-first review showed:

• No indoor air or off-site receptors at risk
• Unsealed rack joints and no pre-discharge checks

Fixes included joint sealing, a filtration insert, and a photo-logged inspection path. After two wet seasons, conditions stabilized and the item was closed and integrated into SPCC/SWPPP exhibits.

Manifold low spot near utilities—closed with work practices

A stained pad beside a utility corridor prompted targeted borings that bounded a small footprint. Groundwater and indoor air screening showed low risk. Controls included:

• A thin barrier under replacement pavement
• A “no-dig without supervisor sign-off” note
• A bedding isolation checklist

Monitoring was retired to visual checks.

What Regulators (and Buyers) Want to See

• A clear statement of exposure threats addressed first
• Lines of evidence used, and what would trigger additional work
• Controls, with named owners and inspection/refresh cycles
• A compact decision log showing how conditions moved to closure and where items now live in SPCC/SWPPP/FRP materials

With that in the file, reviews go quickly—and audits stay uneventful.

10 Steps to Move Legacy Issues to Closure

1. Build a terminal exposure map.
2. Define plausible exposure for each area.
3. Gather right-sized evidence.
4. Install or verify engineering and institutional controls.
5. Create one-page risk registers.
6. Align SPCC/SWPPP/FRP exhibits with field reality.
7. Set simple re-check triggers.
8. Conduct quarterly light-lift reviews.
9. Fold updates into MOC.
10. Write a short closure memo and move to upkeep.

How PPM Helps

PPM implements terminals-first, risk-based closure programs embedded within your SPCC, stormwater, and FRP structures. Our support includes:

• Site walks focused on real exposure pathways
• Right-sized lines-of-evidence plans
• Practical controls (coatings, joint sealing, dewatering SOPs)
• One-page risk registers that live where operators work
• Quarterly cadence, photo logs, and corrective-action tracking

If you have a few “that corner of the yard” legacy items, send the map and recent photos. We’ll return a concise closure plan sized to the risk—and show how to fold it cleanly into your existing programs.