Environmentally Acceptable Lubricants (EAL)
An EAL is the certified intersection of three properties — readily biodegradable, minimally toxic to aquatic life, and non-bioaccumulative. The term comes from the US EPA Vessel General Permit, which requires EALs at every oil-to-sea interface. This guide explains the definition, the criteria and how a product earns the label.
What makes a lubricant an EAL?
"Environmentally Acceptable Lubricant" is a regulatory term, not a marketing one. To qualify, a finished lubricant must satisfy all three of the following at once — passing one or two is not enough:
Readily biodegradable
Breaks down by ≥ 60% within 28 days under an OECD 301 test — full mineralisation, not just loss of the parent molecule.
Minimally toxic
Low acute aquatic toxicity to algae, invertebrates and fish (OECD 201/202/203), above defined LC50/EC50 thresholds.
Non-bioaccumulative
Does not build up in organisms — indicated by a low octanol–water partition coefficient (log Kow).
Because all three must hold together, an EAL is designed as a system from the start — base oil and additives chosen together — rather than a conventional product with a green claim added afterward.
The US EPA VGP and where EALs are required
The driving regulation is the US EPA Vessel General Permit (VGP), which requires the use of EALs in all oil-to-sea interfaces on vessels operating in US waters — unless technically infeasible. Oil-to-sea interfaces include:
- Stern-tube bearings and seals
- Controllable-pitch propellers and thrusters
- Stabilisers, rudder bearings and azimuth thrusters
- Deck machinery, cranes and wire ropes exposed to the sea
Beyond the VGP, European ecolabels and port regulations push EAL adoption across marine, offshore, hydropower and inland-waterway operations.
How the three criteria are tested
An EAL claim rests on laboratory data, not assertion:
Biodegradability
OECD 301B (modified Sturm) measures CO₂ evolution over 28 days; ≥ 60% earns "readily biodegradable".
Aquatic toxicity
OECD 201 (algae), 202 (daphnia) and 203 (fish) establish that the fluid is not acutely toxic.
Bioaccumulation
Partition-coefficient (log Kow) data shows the fluid does not concentrate in tissue.
Bio-based content
ASTM D6866 quantifies renewable carbon where a bio-based claim is also made.
Our testing programme assembles this evidence into a defensible certification file.
Which base oils make a good EAL
EALs map onto the ISO 15380 categories. In practice, most marine EALs are built on synthetic esters (HEES) for their stability and water tolerance, with vegetable oils (HETG) and renewable hydrocarbons (HEPR) used where their properties fit. Hydrolytic stability and water-separation are weighted heavily because these fluids work in constant contact with seawater.
EAL product types
Stern-tube oil
Biodegradable lubricant for the stern-tube bearing — the headline VGP application.
Hydraulic fluid
EAL hydraulics for deck machinery, cranes and stabilisers.
Gear oil
Thruster and deck-gear lubricants in EAL form.
Wire-rope lubricant
Adhesive, biodegradable protection for exposed ropes.
Grease
Water-resistant EAL greases for fittings and bearings.
Gate & dam hydraulics
EALs for hydropower and inland-waterway structures.
Developing and certifying an EAL
Lubechem formulates EALs as a system — selecting the renewable base oil and a low-toxicity, biodegradation-friendly additive package, then proving all three EAL criteria through OECD and ASTM testing and assembling the documentation. We deliver the formula and IP, and can support manufacturing setup for production.
Related guides
EAL FAQ
What is an Environmentally Acceptable Lubricant (EAL)?
A finished lubricant that is simultaneously readily biodegradable, minimally toxic to aquatic life and non-bioaccumulative. The term is defined by the US EPA Vessel General Permit for use at marine oil-to-sea interfaces.
Where does the VGP require EALs?
At all oil-to-sea interfaces on vessels in US waters — stern tubes, controllable-pitch propellers, thrusters, stabilisers, rudder bearings and exposed deck machinery — unless technically infeasible.
Is every biodegradable lubricant an EAL?
No. Biodegradability is only one of the three EAL criteria. A fluid must also pass aquatic-toxicity and bioaccumulation requirements to qualify as an EAL.
What base oils are used in EALs?
Mostly synthetic esters (HEES) for their stability and water tolerance, with vegetable oils (HETG) and renewable hydrocarbons (HEPR) where suitable. They correspond to the ISO 15380 categories.
Can you develop and certify an EAL for us?
Yes. We formulate the product to meet all three EAL criteria, run the OECD and ASTM testing, and assemble the certification file — delivering the formula and IP to you.
Develop a VGP-compliant EAL with confidence.
Stern-tube, hydraulic, gear or grease — formulated to meet all three EAL criteria, tested and documented, with the IP yours.
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