Capstone: a spill prevention and response plan for a fleet maintenance yard

This capstone brings the course together by building a spill prevention and response plan for an invented workplace: Northwind Fleet Services, a company that maintains and fuels about 60 delivery trucks and a few loaders at a single yard. The company, the site and the numbers are invented for teaching, but the problems are real ones found at many yards. Work through each step, then compare your thinking with the worked answers.

The site

Northwind's yard covers about five acres on the edge of a small Ohio town. It has a maintenance shop with four service bays, a parts room and a small chemical storage room; a fuel island with a 6,500-gallon aboveground diesel tank and a 1,300-gallon gasoline tank in a shared concrete dike; a 500-gallon used oil tank beside the shop; a drum storage pad; a vehicle wash bay with an oil-water separator; and a paved parking area. Storm drains in the parking area lead to a ditch along the rear fence, which flows to Cedar Creek, a small trout stream about 500 feet away. The shop floor drains connect to the wash bay separator and then to the municipal sanitary sewer. There is a domestic well on a neighboring property about 400 feet from the fuel island, and the soil is sandy.

Step 1: inventory and risk assessment

The first step is to list every substance and every place it could escape, then rate the risks. The inventory includes diesel, gasoline, used oil, new engine and hydraulic oils in drums, antifreeze, windshield washer fluid, brake cleaner, parts washer solvent, battery acid in stored batteries, diesel exhaust fluid, and wash bay detergents. The table summarizes the main sources and pathways, and the code ranks them.

# Ranking Northwind's spill risks: likelihood (1-5) x consequence (1-5). Scores are a matter of opinion.
risks = [
    ("Fuel delivery overfill",          3, 5),
    ("Truck fuel tank leak in parking", 4, 4),
    ("Drum puncture on drum pad",       3, 4),
    ("Hydraulic hose burst in yard",    4, 3),
    ("Wash bay separator bypass",       3, 3),
    ("Diesel tank failure (in dike)",   1, 5),
    ("Shop chemical spill",             3, 2),
]
for name, l, c in sorted(risks, key=lambda r: r[1] * r[2], reverse=True):
    s = l * c
    print(f"{name:<34} {s:>2}  {'HIGH' if s >= 15 else 'medium' if s >= 8 else 'low'}")

Truck fuel tank leak in parking    16  HIGH
Fuel delivery overfill             15  HIGH
Drum puncture on drum pad          12  medium
Hydraulic hose burst in yard       12  medium
Wash bay separator bypass           9  medium
Shop chemical spill                 6  low
Diesel tank failure (in dike)       5  low

The ranking points to three priorities: fuel deliveries, leaks from trucks parked over storm drains, and the drum pad. A tank failure has a severe consequence but is unlikely, and the dike is the control, so its integrity and rainwater management matter. The wash bay separator is a chronic source that needs maintenance rather than emergency response.

Step 2: prevention

Prevention measures follow from the risks. For the fuel island: check the dike capacity, keep its drain valve locked and inspect rainwater before release; fit and test high-level alarms on both tanks; require an independent level check and an attended delivery with the supplier; label fill pipes; put a spill kit and a drain cover at the island; and fit an insert or valve on the nearest catch basin. For the parking area: inspect trucks for leaks during each service, use drip pans under leaking vehicles until repaired, and mark storm drains with a no-dumping message. For the drum pad: add spill pallets, a roof and bollards; keep only working stock outside; and move the pad away from the catch basin if possible. For the wash bay: pump out and inspect the separator on a schedule and keep records.

# Northwind dike check (metric, Canadian rule). Tank displacement is an estimate.
diesel, gasoline = 25000, 5000
required = max(1.10 * diesel, diesel + 0.10 * gasoline)
gross = 9 * 6 * 0.6 * 1000
displacement = 3000                     # gasoline tank and footings below wall height (estimate)
available = gross - displacement
print(f"Required {required:,.0f} L; available about {available:,.0f} L; margin {available - required:,.0f} L")
rain_mm = 50
print(f"A {rain_mm} mm storm adds {9*6*rain_mm:,} L of water, leaving a margin of {available - required - 9*6*rain_mm:,.0f} L")

Required 27,500 L; available about 29,400 L; margin 1,900 L
A 50 mm storm adds 2,700 L of water, leaving a margin of -800 L

Step 3: equipment

Spill kits go where the risks are: a wheeled kit of at least 65 gallons capacity with drain covers at the fuel island; a 40-gallon kit in the shop; a kit on the drum pad; a kit at the wash bay; and small kits in every service truck. Because the yard drains to a trout stream, the plan adds a cache of oil-only booms and materials for an underflow dam at the rear ditch, near where the storm outfall enters it. Kits are inspected monthly with tamper seals and restocked after any use. Protective equipment in each kit matches the safety data sheets for fuels, oils and the shop chemicals.

Step 4: response levels and roles

The plan defines three levels. Level 1: small spills of known substances on pavement or the shop floor, with no pathway to drains or water, cleaned up by trained staff. Level 2: larger spills, any spill reaching a catch basin, the ditch or soil, or any uncertainty; the shift lead becomes spill coordinator, the site response team responds and regulatory reporting is assessed. Level 3: fire, strong vapor, injuries, a tank or dike failure, or oil reaching Cedar Creek; evacuate the area, call 911 and the spill contractor, and notify regulators. Each shift has a named spill coordinator and backup, a person to make calls and a person to meet responders at the gate.

Step 5: notification

The notification card at each kit lists: 911 for fire, injury or immediate danger; the shift spill coordinator; the operations manager; the National Response Center at 1-800-424-8802 for any oil sheen on the ditch or creek; the state spill line for spills at or above state thresholds or reaching soil or water; the sewer authority for spills to the sanitary sewer; the spill contractor; and CHEMTREC for chemical advice. Because the facility has more than 1,320 gallons of aboveground oil storage and could discharge to Cedar Creek, it needs an SPCC plan, and the plan notes the 60-day reporting rule for qualifying discharges. The neighbor with the well is on the list, to be contacted if a spill reaches soil near the fuel island, after discussion with the regulator.

Step 6: waste, training, drills and review

The plan names a licensed waste contractor, confirms Northwind's RCRA generator category for its used solvent and spill waste, and notes that a large spill could change the category for that month. It sets up a lined, covered storage area for spill waste with labels and accumulation dates. All shop and yard staff receive training on the plan when hired and every year, with hands-on practice placing drain covers and booms. The coordinator team runs two drills a year, one tabletop and one functional, and the plan is reviewed after each drill, each level 2 or 3 spill, at least yearly, and the SPCC plan at least every five years.

Testing the plan with a scenario