Environmental Impact of Improper Oil Disposal

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Used motor oil pollution explained

What Happens When Used Engine Oil Is Dumped Incorrectly?

Improperly discarded motor oil can contaminate soil, stormwater, rivers, groundwater and drinking-water sources. Used oil is slow to degrade, does not dissolve readily in water and may contain fuel residues, metal particles and other contaminants collected while circulating through an engine.

Pouring oil onto the ground, into a street drain, household sink, toilet or ordinary rubbish does not make it disappear. It transfers the pollution to another place—often where cleanup is more difficult, expensive and environmentally damaging.

Water impact Oil can travel through runoff into streams and lakes
Soil impact Persistent contamination can move below the surface
Wildlife impact Oil can coat, poison and disrupt feeding or reproduction
Correct action Keep used oil separate and take it for recycling
See the direct impact Follow the pollution pathway Dispose of oil safely
Oil reaches the environment Rain and surface runoff can move dumped oil from driveways, soil and streets into drains and waterways.
Pollution persists and spreads Used oil degrades slowly and can stick to sediment, shorelines, vegetation, feathers and animal fur.
Recycling prevents the release Cleanly collected used oil can be re-refined or processed instead of becoming a soil and water contaminant.
Recognize unsafe disposal

What Counts as Improper Used-Oil Disposal?

Improper disposal means releasing, abandoning or managing used oil through a route that is not approved for it. The exact legal rules vary by country, state and municipality, but dumping oil onto land, pouring it into drains, mixing it with ordinary rubbish or burning it in unsuitable equipment can create environmental and safety problems.
Common unsafe actions
  • Pouring oil onto soil, gravel or a vacant lot
  • Emptying oil into a street or storm drain
  • Pouring it into a sink, toilet or floor drain
  • Placing liquid oil in ordinary household rubbish
  • Leaving containers outside a closed recycling facility
  • Mixing oil with coolant, fuel, solvent or pesticides
  • Using oil for dust control or weed suppression
  • Burning it in a fire pit, stove or unsuitable heater
Safer management
  • Catch the full oil change in a clean drain pan.
  • Transfer it to a leakproof container.
  • Keep it separate from all other liquids.
  • Label the container “Used Motor Oil.”
  • Store it upright in secondary containment.
  • Confirm a local recycling location.
  • Disclose contamination honestly.
  • Use a licensed collector for business quantities.
Used oil is different from unused petroleum products. EPA defines used oil as petroleum-based or synthetic oil that has been used and has become contaminated by physical or chemical impurities during that use.
Used oil is more than a dark liquid

Why Used Motor Oil Can Be Environmentally Harmful

It does not dissolve readily

Oil can remain as a surface film, attach to sediment or spread along shorelines rather than harmlessly blending into water.

It degrades slowly

Persistent contamination can remain in soil and sediment long after the visible liquid has disappeared from the surface.

It sticks to living surfaces

Oil can coat feathers, fur, plants, insects, fish eggs, shellfish habitat and shoreline organisms.

Burning can create emissions

Uncontrolled burning can produce smoke, soot, gases and contaminated residue rather than safely eliminating the waste.

It burdens drainage systems

Oil entering a drain can be carried to a waterway or create treatment, maintenance and disposal problems.

Dumping wastes a resource

Used oil can be re-refined into lubricant base stock or processed for other regulated uses instead of being discarded.

Used oil may contain more than lubricant. Normal engine operation can introduce dirt, soot, metal wear particles, water, fuel-related compounds and other contaminants. Unknown or mixed oil may require hazardous-waste handling.

EPA’s consumer summary: used motor oil is insoluble, persistent, slow to degrade and capable of carrying toxic chemicals and heavy metals into soil and water.

Read EPA used-oil guidance
Pollution rarely stays where it started

How Dumped Oil Moves Through the Environment

Oil is dumped Driveway, soil, street, rubbish or drain
Rain or leakage moves it Runoff, seepage, broken containers or waste compaction
Oil reaches a pathway Storm drain, stream, soil pores, sewer or landfill leachate
Contaminants spread Surface water, sediment, groundwater, plants and wildlife
Cleanup becomes difficult Collection, excavation, treatment, habitat repair and disposal
Driveway or street disposal Rain can wash oil into gutters and storm drains. Many stormwater systems discharge to local waters without the treatment normally associated with a sanitary sewer.
Dumping onto bare soil Some oil remains near the surface, while lighter compounds and contaminated water can move downward or sideways through the soil.
Oil in household rubbish Containers can leak during storage, collection or compaction. The oil may contaminate collection vehicles, waste facilities or landfill liquid.
Oil in a sink or toilet The oil enters plumbing and wastewater infrastructure. It may interfere with equipment, become part of sludge or pass through treatment pathways not designed for automotive waste.
Oil left outside a recycling centre Abandoned containers can be damaged by vehicles, weather or vandalism, creating an uncontrolled spill at a site that was meant to prevent pollution.
Key lesson: “out of sight” is not the same as safely managed. A drain, rubbish bin or patch of soil only changes where the oil travels next.
A small volume can spread widely

How Used Motor Oil Pollutes Water

EPA consumer guidance states that used oil from one oil change can contaminate up to one million gallons of fresh water. This figure communicates the potential scale of water-quality damage; the actual effect of a release depends on the oil quantity, composition, receiving water, weather, flow and speed of cleanup.

Surface films

Oil can form a visible sheen or film. The film can spread beyond the original spill location and attach to floating material, shorelines and vegetation.

Sediment contamination

Heavier material and oil-coated particles can settle into stream, lake or coastal sediment where organisms feed, reproduce and shelter.

Drinking-water concerns

Oil releases can affect watersheds, reservoirs, wells and treatment sources. Preventing contamination is easier than removing a complex petroleum mixture later.

Oxygen and habitat stress

Oil and associated organic material can contribute to poor habitat conditions and interfere with sensitive aquatic environments.

Long-distance transport

Moving water can carry an oil sheen through roadside drains, ditches, creeks, rivers, wetlands and coastal areas.

Difficult cleanup

Once oil reaches water, responders may need booms, absorbents, recovery equipment, sediment management and specialist wildlife care.

Never wash an oil spill into a gutter. Water and detergent may make the pavement look cleaner while moving the pollution directly toward a storm drain.

Stormwater reality: EPA explains that runoff over hard surfaces can move through storm drains to water bodies without an opportunity for soil, plants or a treatment facility to filter the pollutants.

Read EPA stormwater guidance
Contamination can move below the visible stain

Effects on Soil, Plants and Groundwater

Soil structure and habitat

Oil coats soil particles

A petroleum coating can change how water and air move through soil and can disturb the microorganisms, insects and roots that depend on healthy soil conditions.

Plant stress

Roots may encounter contaminated soil

Oil can physically coat root zones and expose plants to petroleum-related contaminants. Damage depends on the concentration, soil type, plant species and duration.

Downward movement

Some compounds can reach groundwater

Used oil contains a mixture of components. Water moving through contaminated soil can carry mobile compounds toward shallow groundwater.

Property cleanup

Contaminated soil may require removal

A significant release can require sampling, excavation, treatment, disposal or long-term monitoring rather than a simple surface wipe.

Visible stain disappears The absence of a shiny surface does not prove the oil has degraded. It may have soaked into soil, attached to particles or moved with water.
Rain follows the release Rain can spread surface contamination, carry it into nearby drainage features and move dissolved or suspended contaminants deeper into the ground.
Release occurs near a well Stop the source, protect the well area and contact the appropriate environmental or health authority. Do not assume distance at the surface equals protection underground.
USGS research has detected gasoline-related compounds—including benzene and other BTEX compounds—in tested used motor-oil samples. The study supports treating used oil as a potential groundwater-contaminant source rather than harmless dirty lubricant.

Technical source: review the U.S. Geological Survey publication examining used motor oil as a source of MTBE, TAME and BTEX compounds to groundwater.

Open the USGS study summary
Oil harms through coating and toxicity

How Oil Pollution Affects Wildlife

Bird feathers lose water resistance

Oil can disrupt the structure that keeps feathers waterproof and insulating. Birds may become cold, unable to fly normally or spend excessive time preening.

Mammal fur loses insulation

Oil can reduce the insulating ability of fur-bearing animals, increasing heat loss and the risk of hypothermia in aquatic environments.

Animals ingest oil while cleaning

Birds and mammals can swallow oil when licking fur or preening feathers, exposing internal organs to toxic compounds.

Fish and shellfish are exposed

Oil mixed into the water column or attached to sediment can affect fish, shellfish, eggs and larvae in feeding and nursery habitats.

Turtles and marine mammals are vulnerable

Animals may inhale vapours, encounter floating oil, ingest contaminated material or experience effects on lungs, immunity and reproduction.

Food chains can be disrupted

Damage to insects, plankton, plants, eggs, larvae and shellfish can affect species that depend on them for food and habitat.

Do not attempt to wash an oiled wild animal yourself. Handling can stress the animal and expose the rescuer to contaminants. Contact an authorised wildlife-rehabilitation or environmental-response organisation.

NOAA explains two primary forms of harm: physical fouling or coating, and toxic exposure through ingestion, inhalation or contact.

Read NOAA’s wildlife-impact explanation
Storm drains and sanitary sewers are different

Why Oil Should Never Go Down Any Drain

Drain type Where it may lead What oil can do Correct action
Street storm drain Drainage ditch, stream, river, wetland, lake or ocean Oil may reach natural water without wastewater treatment. Keep oil, wash water and absorbent away from gutters.
Household sink or toilet Sanitary sewer or septic system Oil can burden plumbing, treatment systems, sludge management or septic performance. Collect the oil separately for recycling.
Garage floor drain Sanitary sewer, stormwater system, oil separator, sump or unknown outlet An unidentified connection can discharge oil to an inappropriate system. Identify the drain and use dry spill-cleaning methods.
Yard or foundation drain Soil, ditch, storm system or receiving water Oil can bypass normal waste controls and spread underground or off the property. Prevent entry and report significant contamination.
Simple rule: no automotive oil, fuel, coolant, brake fluid, solvent or oil-contaminated wash water belongs in a drain unless a specifically permitted industrial system is designed and authorised to receive it.

EPA’s nonpoint-source guidance: storm drains can carry oil, grease and toxic chemicals into lakes, streams, rivers and wetlands.

Read EPA nonpoint-source pollution guidance
Burning is not the same as recycling

Environmental Risks of Burning Used Motor Oil Improperly

Used oil should be burned only in equipment and under conditions allowed by the applicable environmental rules. An open fire, homemade burner or unsuitable space heater does not provide the combustion control, ventilation, monitoring or pollution management used by regulated facilities.

Smoke and particulate pollution

Incomplete or uncontrolled combustion can produce visible smoke, soot and fine particles that travel downwind.

Contaminant emissions

Used oil may contain metals, fuel residues, halogens or other contaminants that change the emissions and ash produced during burning.

Indoor exposure

Burning in a garage, shed or poorly ventilated area can expose occupants to combustion products and increase fire risk.

Contaminated ash or residue

Combustion does not make every contaminant disappear. Metals and other noncombustible material can remain in ash or deposits.

Equipment damage and fire

Unknown water, fuel or solvent contamination can cause poor burning, flare-ups, corrosion, blockages or unsafe operation.

Regulatory violations

Local air-quality, waste, fire and building rules may prohibit open burning or restrict which heaters and fuels can be used.

Do not burn unknown or mixed automotive waste. Oil contaminated with gasoline, solvent, brake cleaner, coolant, pesticides or PCBs may require specialised handling and disposal.
Regulated energy recovery is different. EPA recognises controlled used-oil processing and burning in certain regulated boilers, furnaces or approved equipment. That does not authorise household burning.
Pollution costs extend beyond the person who dumped it

Community and Economic Consequences

Emergency response Public agencies may need staff, vehicles, booms, absorbents and specialist contractors.
Drain cleaning Oil-contaminated catch basins, separators and pipes may require cleaning and waste disposal.
Water treatment Protecting or restoring water sources can require monitoring, treatment changes and source investigation.
Soil remediation Contaminated soil may need testing, excavation, treatment, transport and approved disposal.
Wildlife response Trained responders may be needed to recover, clean, rehabilitate and monitor affected animals.
Property impacts Odours, stains, contaminated wells and environmental records can affect land use and property decisions.
Business disruption A contaminated collection tank can require shutdown, testing, decontamination and costly disposal.
Lost resource value Oil that could have been re-refined or processed becomes cleanup waste instead.
Mixing contaminated oil into a clean collection tank can multiply the problem. EPA warns that PCB-contaminated oil can cause an entire tank volume and affected trucks or equipment to require specialised management and decontamination.
What each disposal shortcut actually does

Environmental Impact by Disposal Method

Disposal shortcut Immediate result Environmental pathway Better alternative
Pouring oil onto soil Visible stain and contaminated ground Runoff, root-zone exposure, deeper soil migration and possible groundwater impact Use a sealed container and recycling centre.
Pouring oil into a storm drain Oil disappears from the street Direct or rapid movement to streams, wetlands, rivers, lakes or coastal water Keep drains protected and recycle the oil.
Pouring oil into a sink or toilet Oil enters household plumbing Sewer or septic-system contamination, treatment burden and oily residual waste Use a household hazardous-waste or oil-recycling service.
Putting oil in normal rubbish Container enters collection system Leaks during handling or compaction, contaminated vehicles and landfill liquids Use a dedicated liquid-oil drop-off.
Using oil for dust control Road or soil surface becomes oily Repeated runoff, direct soil exposure and contact with people, animals and vegetation Use an approved dust-control material and authorised waste route.
Burning oil outdoors Smoke, odour and residue Air emissions, fallout, contaminated ash and fire risk Recycle it or use an authorised waste-oil handler.
Correct common disposal myths

Used Motor Oil Disposal Myths

“A small amount on gravel will disappear.”
The stain may become less visible.
The oil can remain in soil, spread with rain or move below the surface.
“Storm drains go to a treatment plant.”
This is not true for many drainage systems.
Stormwater commonly flows to local waterways with little or no treatment.
“Detergent makes an oil spill harmless.”
Detergent may break the oil into smaller droplets.
It can spread contamination and make recovery more difficult.
“Oil is natural, so soil can absorb it safely.”
Crude petroleum exists naturally underground.
Used engine oil is a contaminated industrial waste that does not belong in surface soil.
“Burning destroys all contaminants.”
Combustion destroys some organic material.
Poor combustion creates emissions, and metals or noncombustible contaminants can remain.
“Mixing it with fresh oil makes it recyclable.”
Dilution changes the concentration.
It does not remove contamination and can ruin a larger volume of otherwise recyclable oil.
Act before the oil spreads

What to Do After an Accidental Oil Spill

1. Stop the source Set the container upright, close a valve or move oil into a sound container when this can be done safely.
2. Protect drains and water Block the route to gutters, soil, streams and drains. Do not use a hose.
3. Contain the edges Use absorbent socks, sand, clay absorbent or another locally approved material to prevent spreading.
4. Recover free liquid Collect reusable or recyclable free-flowing oil into a leakproof container where possible.
5. Collect contaminated material Bag or containerise absorbent, soil, rags and protective equipment according to local waste instructions.
6. Report serious releases Contact the environmental or emergency authority when oil reaches water, a public drain or a sensitive area.
Photograph the spill safely. Record the source, approximate area, nearby drains and any visible movement toward water.
Estimate the quantity. Use the container size, missing volume or engine capacity to give responders a practical estimate.
Identify known contaminants. State whether the oil contains coolant, fuel, solvent, brake cleaner, pesticides or unknown liquid.
Do not bury contaminated absorbent. Store cleanup material securely until the local waste authority confirms the correct disposal route.
Repair the failed container or equipment. Do not refill a cracked drain pan, leaking drum or damaged storage tank.
Reinspect after rain. Look for a sheen, staining or movement beyond the original spill area.
Seek urgent help when: oil enters a stream or storm drain, reaches a drinking-water well, creates a fire hazard, affects wildlife or exceeds what you can safely contain.

EPA cleanup principle: contain the spill, recover as much free oil as possible and manage the recovered oil as used oil rather than washing it away.

Review EPA spill-management guidance
Keep mixed waste out of clean recycling tanks

How Contamination Makes Used Oil Harder to Recycle

Clean used engine oil Keep it sealed and separate. It may be accepted by a household collection site, automotive retailer or authorised recycling centre.
Oil mixed with coolant Do not place it in a normal oil-recycling tank. Contact a household hazardous-waste facility and disclose the mixture.
Oil mixed with petrol, gasoline or diesel fuel Treat it as a potentially flammable mixed waste. Keep it away from ignition sources and obtain facility instructions before transport.
Oil mixed with solvent or brake cleaner Use a hazardous-waste route. Solvent contamination can change regulatory status, fire risk and recycling compatibility.
Unknown old container Do not smell, pour, dilute or combine it. Keep it sealed and describe it as an unknown automotive liquid.
Possible PCB contamination Commercial and municipal handlers must use specialised testing and regulatory procedures. Never dilute suspected PCB oil.
One contaminated container can affect a much larger collection tank. The receiving facility may have to test, isolate, decontaminate or dispose of the entire mixed volume.

PCB warning: EPA explains that introducing PCB-contaminated oil into a non-PCB collection can require costly regulated disposal and decontamination of tanks and transport equipment.

Read EPA PCB contamination guidance
Turn a pollution risk into a recyclable resource

How to Dispose of Used Motor Oil Correctly

Confirm the engine’s oil capacity before draining. Use a drain pan large enough for the full oil quantity so an overflow does not become a driveway or soil spill.
Use clean oil-change equipment. Do not use a drain pan that contains coolant, fuel, solvent, water or household chemicals.
Transfer oil into a leakproof container. The original oil jug or a purpose-made used-oil container is often practical when accepted locally.
Secure and label the container. Tighten the cap, wipe the outside and mark it clearly as “Used Motor Oil.”
Keep the oil separate. Use different containers for coolant, brake fluid, fuel and unknown liquids.
Drain the oil filter. Keep the filter in a separate leak-resistant bag or container and confirm whether the recycling location accepts it.
Find an authorised collection location. Check local government waste programs, automotive-parts stores, repair shops or a regional used-oil stewardship program.
Call before travelling. Confirm household acceptance, quantity limit, opening hours, filter recycling and whether the tank currently has space.
Transport the oil upright. Place the sealed container in a rigid secondary tub and secure it against tipping.
Follow staff instructions. Do not pour into a tank, leave a container or combine materials until an attendant directs you.
Keep a maintenance record. Record the oil change, oil quantity, filter, recycling location and date.
Use a licensed collector for commercial oil. Workshops, fleets, farms and paid mobile mechanics may be subject to business-waste storage, transport and recordkeeping rules.

Suitable storage habits

  • Clean container with a tight screw cap
  • Clear “Used Motor Oil” label
  • Upright position
  • Secondary tray or plastic tub
  • Covered area away from rain
  • Protected from children and pets

Containers to avoid

  • Open buckets
  • Cracked drain pans
  • Food or beverage containers
  • Containers that held bleach or pesticide
  • Unlabelled bottles
  • Containers with damaged caps

Find a recycling route: EPA recommends checking with local automotive maintenance facilities, waste collectors and government waste officials for an approved used-oil drop-off.

Use EPA’s consumer recycling guidance
Recycling prevents pollution and conserves resources

Environmental Benefits of Recycling Used Oil

Prevents soil and water pollution

Secure collection keeps oil out of drains, soil, wetlands, rivers and groundwater pathways.

Recovers valuable base oil

Used oil can be re-refined to remove impurities and produce base stock for new lubricants.

Reduces demand for crude resources

Re-refining uses a lubricant resource that has already been extracted and processed rather than discarding it after one use.

Uses less processing energy

EPA states that producing re-refined base stock requires less energy than producing base stock from crude oil.

Recovers metal filters

Properly drained steel oil filters contain reusable scrap metal and additional recoverable oil.

Supports a circular system

Re-refined oil can return to use as a lubricant, extending the useful life of the original petroleum resource.

EPA comparison: one gallon of used motor oil can provide the same 2.5 quarts of lubricating oil as 42 gallons of crude oil.
Businesses need stronger controls

Environmental Responsibilities for Workshops and Fleets

Label storage clearly

Use tanks and containers marked for used oil so employees do not add solvents, coolant, fuel or unknown waste.

Use sound containers

Inspect drums, tanks, valves and hoses for corrosion, cracks, impact damage and leakage.

Provide secondary containment

A berm, tray or contained floor can keep a leak from reaching soil, drains or surface water.

Train employees

Staff should know which liquids may enter the used-oil tank, how to report a spill and where response equipment is stored.

Use authorised transporters

Commercial quantities may require registered or licensed collection, transport, documentation and approved processing.

Maintain spill equipment

Keep drain covers, absorbent booms, reusable pads, containers and personal protective equipment available.

State and local rules may be stricter than national minimums. Businesses should verify storage, transport, recordkeeping, spill-reporting and hazardous-waste requirements with the relevant environmental authority.

U.S. business guidance: EPA summarises used-oil storage, recycling, transport, spill response and federal management standards under 40 CFR Part 279.

Read EPA business used-oil guidance
Prevent the next release

Used-Oil Pollution Prevention Checklist

Before an oil change

  • Confirm the engine-oil capacity.
  • Use a drain pan larger than the full capacity.
  • Check that the pan is clean and undamaged.
  • Prepare a leakproof storage container.
  • Protect nearby drains.
  • Have absorbent material ready.
  • Confirm a recycling location.

After an oil change

  • Transfer the oil without mixing fluids.
  • Tighten and inspect the cap.
  • Label the container.
  • Drain and contain the filter separately.
  • Clean small drips with absorbent.
  • Store everything in secondary containment.
  • Take it to the confirmed collection point.

Call an authority when

  • Oil enters a storm drain.
  • Oil reaches a stream, pond or wetland.
  • A drinking-water well may be affected.
  • Wildlife contacts the oil.
  • The spill contains fuel or chemicals.
  • The volume exceeds safe household cleanup.

Information to provide

  • Exact location
  • Estimated quantity
  • Time of release
  • Known contaminants
  • Nearby drains or water
  • Actions already taken
  • Photographs when safe
Oil-disposal environmental FAQs

Frequently Asked Questions

Why is used motor oil harmful to the environment?

Used motor oil is persistent, slow to degrade and able to carry dirt, metal particles, fuel-related compounds and other contaminants. It can pollute soil, stormwater, groundwater and wildlife habitat when it is released improperly.

How much water can one oil change contaminate?

EPA consumer guidance states that used oil from one oil change can contaminate up to one million gallons of fresh water. The actual impact of a spill depends on its volume, composition, location, water flow and speed of cleanup.

What happens when motor oil is poured onto the ground?

The oil can coat soil particles, affect root zones and soil organisms, spread with rainwater and move below the visible surface. Mobile contaminants may eventually reach drainage systems or groundwater.

Why should motor oil never go into a storm drain?

Storm drains commonly carry runoff directly to streams, rivers, wetlands, lakes or coastal water without conventional wastewater treatment. Oil poured into the drain can therefore become direct water pollution.

Can I pour used motor oil down a sink or toilet?

No. Oil can burden household plumbing, septic systems, sewer infrastructure and wastewater treatment. Collect it in a leakproof container and take it to an approved used-oil recycling or hazardous-waste facility.

How does oil pollution harm birds and animals?

Oil can destroy the water resistance of feathers and the insulation of fur. Animals may also swallow oil while cleaning themselves, inhale vapours or consume contaminated food, resulting in poisoning and other health effects.

Is it safe to burn used oil at home?

Used oil should not be burned in an open fire, homemade burner or unsuitable heater. Improper burning can produce smoke, particles, toxic emissions, contaminated ash and fire hazards. Only authorised equipment and regulated operations should burn eligible used oil.

Can used motor oil be recycled after contamination?

Clean used oil is widely recyclable, but oil mixed with coolant, fuel, solvent, water or chemicals may be rejected from normal collection tanks. Keep the mixture sealed and ask a hazardous-waste facility for the correct route.

What should I do if oil reaches a storm drain?

Stop the source, prevent additional oil from entering the drain and contact the local environmental, public works or emergency authority promptly. Do not use water or detergent to wash the remaining oil into the drain.

Why is recycling better than disposing of motor oil?

Recycling prevents soil and water pollution while recovering a valuable lubricant resource. Used oil can be re-refined into new base oil, processed for regulated energy recovery or used as an industrial raw material.

Official-source review

Official Sources Used for This Guide

Used-oil disposal, spill reporting and business-waste requirements differ by country, state and municipality. Check the current rules of the environmental and waste authorities serving the location where the oil was generated.

Last official-source review: July 31, 2026.

Independent information notice: EngineOiil-Capacity.com is an independent informational website. It is not an environmental regulator, waste authority, emergency-response service or recycling contractor. Spill-reporting thresholds, disposal rules, accepted materials and penalties vary by location. Contact the appropriate local environmental or emergency authority when oil reaches water, a storm drain, a well, wildlife habitat or an area that cannot be safely contained.