Is Motor Oil Toxic to Humans and Animals?

by Alastair | Last Updated: September 8, 2023

Motor oil is used to lubricate and protect your vehicle from wear and tear caused by heat and friction. Yet, despite its protective properties, motor oil is full of ingredients that can cause people and animals harm when touched or ingested. So, yes, motor oil is toxic to humans and animals. Let’s discuss the extent of that toxicity and how to protect yourself and the environment from exposure.

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Understanding What Makes Motor Oil Toxic

In order to understand how motor oil is toxic to humans and animals, you must know how it is made. Rather than motor oil’s chemical makeup, it is its physical substance that is the issue. Engine oil is a hydrocarbon, a compound composed of hydrogen and carbon atoms. Hydrocarbons come in various forms, yet they all share an oily texture when in their liquid state. The peril arises when these oily substances are ingested, as they have the potential to enter the airway or be inhaled during vomiting—which is known as aspiration.

Aspiration can be incredibly irritating and may lead to infections. The proximity of the airway to the esophagus plays a pivotal role, and the concept of viscosity (a substance’s flow properties) comes into play—hydrocarbons with low viscosity (thin consistency) are more likely to be aspirated than those with high viscosity (thick consistency).

So while motor oil tends to have viscosity, it also has fumes that can be irritating as well.

The Toxic Contaminants in Used Motor Oil

Used motor oil introduces an additional layer of concern due to the presence of contaminants that are absent in fresh oil. The exposure of motor oil to high heat in operational vehicles leads to the formation of new chemicals that can be more toxic than the oil itself.

Moreover, as the engine oil circulates through the motor’s moving parts, it begins to collect heavy metals and other contaminants. This is why proper disposal of used motor oil is so crucial to protecting the environment. These harmful substances present in used motor oil, including benzopyrene and polycyclic aromatic hydrocarbons (PAHs) are highly toxic and carcinogenic.

How Motor Oil Affects Humans and Animals

Here is a glimpse at what happens should you or another living thing consume, touch, or inhale motor oil—both new and used:

Precautions and Safety Measures When Handling Motor Oil

Given the potential risks associated with motor oil exposure, it’s essential to take proper precautions when working with motor oil or being in its vicinity:

Final Thoughts on Motor Oil Toxicity

Is motor oil toxic to humans and animals? Yes. That is why you should be careful when changing your motor oil and disposing of the substance. Although motor oil is crucial to the function of your vehicle, do not underestimate its ability to cause harm. Even a small mistake can harm you or the environment.