Why spills matter

A spill is any release of a liquid, solid or gas from where it is supposed to be into where it is not. Most spills at work are small: a few litres of hydraulic oil from a burst hose, a jug of cleaning chemical knocked off a shelf, a drip tray that overflowed overnight. Some are large: a fuel tank that fails, a tanker truck that rolls over, a tailings dam that gives way. Small or large, a spill can hurt the people nearby, damage soil, water and wildlife, shut down a business and lead to fines, cleanup bills and lawsuits that last for years.

This course is about preventing spills at ordinary workplaces and responding safely and correctly when they happen. It is written for workers, lead hands and supervisors at places such as fleet yards, warehouses, farms, construction sites, plants, laboratories, schools and stores. It is awareness and first-responder training. It does not qualify you as a hazardous materials technician, and it does not replace the site-specific training your employer must give you on its own spill plan, equipment and chemicals. Where your work involves responding to large releases of hazardous substances, your employer must provide more advanced training under provincial occupational health and safety law and its emergency response plan.

What counts as a spill

The word spill covers many kinds of release. Liquids are the most common: fuels, lubricating and hydraulic oils, antifreeze, solvents, paints, acids, caustics, pesticides, liquid fertilizers, milk and other food products, and wastewater. Solids can spill too: powders, granular fertilizer, cement, contaminated soil and mine tailings. Gases and vapours escape from cylinders, tanks and lines. A spill does not have to be dramatic. A slow drip from a valve that runs for weeks can release more than a sudden break, and because nobody sees it, it often does more damage.

Regulators usually care about where a spill goes as much as how big it is. A litre of oil on a sealed concrete floor inside a building with no drains is a housekeeping problem. The same litre poured into a storm drain that empties into a creek is pollution of fish habitat, and in many jurisdictions it must be reported. Throughout this course you will see the same idea: the pathway from the spill to people and the environment decides how serious it is and what the law requires.

Milk and syrup appear in that table deliberately. Many people assume only toxic chemicals cause environmental harm. But organic liquids such as milk, juice, beer wastes and sugar solutions are food for bacteria. When they reach a stream, bacteria multiply and use up the dissolved oxygen in the water, and fish suffocate. A tanker of milk spilled into a small creek can kill fish for kilometres downstream. This is why environmental laws often define a harmful substance by its effect, not by a list.

Four spills that changed the rules

Some spills are remembered because of their size, some because of the lessons they taught. The four cases below come from very different industries, but each one shows how a spill can travel far beyond its source and how expensive and slow the recovery can be.

On 6 July 2013, a runaway train of crude oil tank cars derailed and burned in the centre of Lac-Mégantic, Quebec, killing 47 people. HSE-250 covers the transport lessons. From a spill point of view, roughly six million litres of crude oil escaped. Much of it burned, but oil also soaked into the soil of the downtown and flowed through storm sewers into Lac Mégantic and the Chaudière River, where it affected drinking water supplies downstream. Years of soil excavation and treatment followed, and the downtown had to be rebuilt on cleaned ground.

In July 2010 a pipeline near Marshall, Michigan, ruptured and released diluted bitumen, a heavy oil thinned with lighter hydrocarbons so it can flow through pipes, into a creek that feeds the Kalamazoo River. Estimates put the release at roughly 3.2 million litres (about 843,000 US gallons). The leak went on for many hours before it was stopped, partly because alarms were misread as other problems. Once the lighter thinning components evaporated, much of the heavy oil sank into the river sediment instead of floating where booms could collect it. The cleanup took years and cost more than a billion dollars, and it changed how responders plan for oils that sink.

On 4 August 2014, the tailings storage facility at the Mount Polley copper and gold mine in British Columbia failed. The breach released roughly 25 million cubic metres of water and mine tailings into Polley Lake, Hazeltine Creek and Quesnel Lake. Hazeltine Creek was scoured and buried. An expert panel found the main cause was a weak layer in the foundation that had not been identified in the design. The case is a reminder that a spill can be a slurry of mostly water and fine solids, and that dams and impoundments are containment structures that must be designed and inspected as seriously as tanks.

On 24 March 1989, the tanker Exxon Valdez ran aground in Prince William Sound, Alaska, and spilled about 41 million litres (about 11 million US gallons) of crude oil. Oil eventually reached around 2,000 kilometres of shoreline. Seabirds, sea otters, seals and fish populations were badly hurt, and some effects lasted for decades. The spill led directly to the US Oil Pollution Act of 1990, which strengthened requirements for spill prevention, response planning and liability, and influenced spill rules around the world, including double hulls for tankers.

The workplace spill you are more likely to see

Those famous cases are not typical. The spills most workers will see are small, local and preventable: a fuel nozzle left in a jerrican that overflows, a forklift that punctures a drum, a hose that splits on an excavator, a delivery driver who connects to the wrong tank fill pipe, a drum of used oil stored outside without a lid so rain overflows it. Each of these can usually be stopped and cleaned up in minutes by trained people with the right equipment. Each can also turn into a much bigger problem if no one acts, if the spill reaches a drain, or if people respond in a way that puts themselves in danger.

Small spills add up. A transport company with fifty trucks that each leak a few drops of oil a day is releasing hundreds of litres a year onto its yard, and rain washes that oil into storm drains. Regulators increasingly look at these chronic sources, not just big accidents. The good news is that small spills are also where prevention pays off most: drip trays, maintenance, good storage, and a culture where people report and fix leaks quickly.

# A slow drip adds up (illustrative numbers).
drops_per_minute = 10        # a modest drip from a loose fitting
ml_per_drop = 0.05
minutes_per_year = 60 * 24 * 365
volume_l = drops_per_minute * ml_per_drop * minutes_per_year / 1000
print(f"One fitting dripping {drops_per_minute} drops a minute releases about {volume_l:.0f} L a year")
print(f"That is about {volume_l / 3.785:.0f} US gallons, from one unnoticed drip")
for fittings in (5, 20, 50):
    print(f"{fittings:>3} dripping fittings across a fleet: about {fittings * volume_l:,.0f} L a year")

One fitting dripping 10 drops a minute releases about 263 L a year
That is about 69 US gallons, from one unnoticed drip
  5 dripping fittings across a fleet: about 1,314 L a year
 20 dripping fittings across a fleet: about 5,256 L a year
 50 dripping fittings across a fleet: about 13,140 L a year

Harm to people, the environment and the business

Spills hurt people first. Flammable liquids can ignite and burn. Vapours from fuels and solvents can make people dizzy, sick or unconscious in enclosed spaces. Acids and caustics burn skin and eyes. Some chemicals react with each other or with water to release toxic gases. Slips on oil and glycol cause many injuries. Responders who rush in without protection are often among the casualties, which is why the first rule of spill response, covered in lesson 7, is to protect yourself and others before touching the spill.

The environment is harmed through soil, surface water, groundwater and air. Oil coats birds and smothers plants. Even small amounts of some substances are toxic to fish and insects. Fuels and solvents that soak into the ground can reach groundwater and contaminate wells for decades, as lesson 8 explains. Nutrients from fertilizer and manure cause algae blooms. Sediment from a solids spill buries spawning beds.

The business pays as well. Cleanup of contaminated soil and groundwater is expensive, and the cost rises steeply the longer a spill goes unnoticed. Operations may be shut down. Neighbours may sue. Insurers may raise premiums or refuse coverage. Regulators can order cleanup, impose fines and, in serious cases, prosecute companies, directors and individuals. Reputations suffer when a spill makes the news.

Penalties can be large. Under the federal Fisheries Act, depositing a deleterious substance into water frequented by fish is an offence, and a corporation convicted on indictment of a first offence faces a fine of $500,000 to $6 million, rising to $1 million to $12 million for a later offence, with lower ranges for small-revenue corporations and individuals. Provinces have their own environmental offences and penalties. Lesson 3 explains how these laws fit together.

# Pool volume estimate: area x average depth (works for any shape if you estimate area).
def pool_volume_l(length_m, width_m, depth_mm):
    return length_m * width_m * (depth_mm / 1000) * 1000

for l, w, d in [(4, 2.5, 5), (1.5, 1.0, 3), (10, 6, 2)]:
    v = pool_volume_l(l, w, d)
    print(f"{l} m x {w} m at {d} mm deep -> {v:6.1f} L  ({v / 3.785:5.1f} US gal)")

4 m x 2.5 m at 5 mm deep ->   50.0 L  ( 13.2 US gal)
1.5 m x 1.0 m at 3 mm deep ->    4.5 L  (  1.2 US gal)
10 m x 6 m at 2 mm deep ->  120.0 L  ( 31.7 US gal)

The rest of this course

The following lessons work through the problem in a logical order. Lesson 2 looks at where spills happen at work. Lesson 3 maps the laws. Lessons 4 and 5 cover prevention and planning. Lesson 6 covers spill kits. Lesson 7 is the core response procedure. Lessons 8 and 9 look at spills to land and water. Lesson 10 covers cleanup and waste, lesson 11 covers reporting, and lesson 12 brings everything together in a plan for a fleet maintenance yard. Spills during transport are covered in HSE-250, chemical storage in HSE-312 and fuel station spills in HSE-351.