Hydraulic fluids are usually safe in closed systems, but can be dangerous to people and the environment if there is high pressure or temperature, or if there is a leak. This article will explain the risks of hydraulic fluids and how to control them.
Is Hydraulic Fluid Dangerous?
Hydraulic fluids are not highly toxic substances, but they can be dangerous in some situations.
Normally, hydraulic systems are closed. The liquid moves through the lines and does not touch the workers when the risk is low. Problems usually happen when there is a leak, injection, or unusual heating of the equipment.
The fluid may be exposed when the system needs to be serviced or when replacement parts are needed. If you are responsible for maintenance work and you disassemble a line without fully releasing the pressure, the fluid may spray out at high pressure. Fluid under high pressure can more easily go through things and hurt them.
The safety of different types of hydraulic fluids is also different. Mineral-based hydraulic fluids are more common and can catch fire. Synthetic hydraulic fluids stay more stable at high temperatures. Flame-retardant hydraulic fluids are specifically designed for use in environments with high temperatures or open flames to reduce the risk of fire.
So, whether or not a hydraulic fluid is dangerous depends on the pressure, temperature, and how it is exposed. The danger is more from how it is used than from the fluid itself.
Why Can Hydraulic Fluid Become Hazardous?
The main reasons why hydraulic fluids can become dangerous are related to additive composition, system pressure, and operating temperature.
Chemical Composition
Hydraulic fluids contain additives such as antiwear and antioxidants. These components protect equipment, but can cause skin and lung irritation if you breathe in the liquid for a long time or if it breaks down at high temperatures.
System Pressure
Many industrial hydraulic systems operate at pressures between 1000 and 5000 psi. Some heavy equipment can be even more sensitive to pressure. If pipes burst or become loose, high-pressure fluid can come out all at once. The higher the pressure, the greater the risk of injury.
Temperature
Most mineral-based hydraulic fluids have a flash point of about 150-300°C. When the temperature gets close to this range, the fluid won’t flash at all. As the oil gets close to this range, there’s a higher chance of it catching fire. If the fluid is sprayed as a mist, it is more likely to catch fire on hot surfaces or from an ignition source.
What Health Risks Are Associated with Hydraulic Fluid?
Hydraulic fluids can cause skin irritation, eye irritation, respiratory problems, and long-term exposure. The risk depends on how long they are exposed, the concentration, and the environment.
Skin Contact
Hydraulic oil can remove oil from the surface of the skin, which can make the skin dry or red. If you are exposed to it for a long time, it can cause skin problems. Some additives can make skin more sensitive. If you often come into contact with the fluid, you are more likely to have skin problems.
Eye Exposure
If oil gets in your eyes, it might cause stinging, tearing, or blurred vision for a short time. There is more of a chance of splashing when you are working near high-pressure systems. You may still feel unwell even after you have been outside for a short time.
Inhalation
In open environments, the risk of breathing in is usually low. However, in small spaces or spaces with poor ventilation, oil mist may build up. You are more likely to be exposed to harmful substances if you work in equipment rooms or underground spaces. Breathing in oil mist can cause a sore throat or a cough.
Long-Term Exposure and Exposure Limits
The risk of long-term exposure is related to the type of oil. Some of the components can be dangerous in the workplace. OSHA has suggested ‘Permissible Exposure Limits’ (PEL) to limit the amount of certain chemicals in the air that workers can breathe. For more information, check the product’s Safety Data Sheet (SDS).
How Dangerous Are High-Pressure Injection Injuries?
Injuries from high-pressure hydraulic fluid injection are always serious medical emergencies, even if the wound appears to be small. Many industrial hydraulic systems are pressurised between 2,000 and 5,000 psi. This is enough pressure to shoot oil directly into the tissue just under the skin.
When a pipe bursts or a fitting comes loose, the oil shoots out like a tiny, super-fast jet. The jet can go deep into the skin. You might only see a small hole, but the oil has entered the deeper layers of tissue.
When the oil enters the body, it can cause swelling and inflammation. Some of the tissues might die because the blood supply is blocked. The first signs of the problem are often very mild and can be hard to spot.
If you get an injection injury, go to the hospital straight away for treatment. Don’t wait for the symptoms to get worse or treat the wound yourself. You will need to explain to your doctor that this was a high-pressure hydraulic fluid injection accident so that it can be properly evaluated and treated.
Is Hydraulic Fluid Flammable?
Most mineral-based hydraulic fluids are liquids that can catch fire if they are very hot or sprayed.
Flash Point and Auto-Ignition Temperature
The flash point of mineral-based hydraulic fluids is typically between 150–300°C, depending on the specific oil type. The flash point is the temperature at which oil vapours can catch fire if they come into contact with an open flame. Be careful if the surface temperature of the equipment gets close to this range.
The auto-ignition temperature is usually higher than the flash point. When oil gets to this temperature, it can catch fire even without a flame. So, when you’re working near something that’s very hot, check both the oil temperature and the surface temperature of the equipment.
Spray Increases Fire Risk
When high-pressure lines burst, oil may come out as a fine spray. This spray can catch fire more easily when it mixes with air. If the spray comes into contact with hot metal surfaces or electrical sparks, there is a greater risk of fire.
Fire-Resistant Fluids
These fluids are made to be used in places where they can get very hot or where there is a lot of fire risk. These fluids are less likely to catch fire, but they can still catch fire. If you’re working near metallurgical or thermal processing equipment, choose the right fluid type based on how it’s being used.
So, how easily the hydraulic fluid can catch fire depends on the temperature, how it is leaking and what type of fluid it is.
What Environmental Risks Do Hydraulic Fluid Leaks Pose?
Hydraulic fluid leaks can contaminate soil and water, which is bad for the environment and breaks the law. When systems are sealed off, they don’t have much of an effect on the environment. But problems can happen if there are leaks and fluid gets into the ground or drainage systems.
Soil Contamination
When water seeps into the soil, it sticks to the soil particles. Mineral-based hydraulic fluids break down slowly and can stay in the ground for a long time. If you’re using outdoor equipment or working on a construction site, make sure you deal with any leaks quickly to stop oil from spreading.
Water Contamination
If oil gets into storm drains or rivers, it makes an oily film on the water’s surface. This film stops water from moving around and is bad for watery environments. Be very careful to stop leaks when working near water.
Biodegradable vs. Mineral Oil
Biodegradable hydraulic fluids break down more quickly in the natural world, but they still need to be disposed of properly. Mineral-based hydraulic fluids are more stable and last longer. When choosing a fluid, think about how it will be used and what the environment is like.
Cleanup and Compliance
If there is a spill, contain it and clean it up straight away. Dispose of waste oil according to the rules. Set up clear on-site procedures for dealing with spills that follow the law.
What Safety Measures Reduce Hydraulic Fluid Risks?
If you follow standard operating procedures and basic safety rules, you can greatly reduce the risks associated with hydraulic fluid. Most accidents happen when people are maintaining or taking apart the equipment. If you are doing maintenance work, prepare in advance.
Use Proper PPE
When you’re dealing with liquids, make sure you wear gloves and glasses to protect your eyes. Gloves stop your skin from touching the water, and glasses stop water from splashing into your eyes. This protection is especially important when working near high-pressure systems.
Release Pressure Before Service
Make sure you always fully relieve system pressure before doing any maintenance. Many hydraulic systems operate at pressures between 1000 and 5000 psi. If you disconnect fittings without pressure relief, oil can spray out very quickly. Make sure the pressure gauge reads zero before you continue.
Check for Leaks Regularly
Check the hoses, fittings and seals regularly. If you ignore minor leaks, they can get worse and lead to high-pressure jets or big spills. It’s important to do a simple check regularly to spot problems early.
Store Away from Heat Sources
Keep hydraulic fluid away from open flames and hot surfaces. Make sure storage areas have good air circulation and keep them away from welding or heating equipment. The closer the temperature gets to the flash point, the higher the fire risk.
Follow the SDS
Every hydraulic fluid has a Safety Data Sheet (SDS). The SDS lists the protective requirements and handling procedures. Use the SDS to help you write on-site operating procedures.
What Should You Do If Exposure Occurs?
If there is a leak in the hydraulic fluid, you should deal with it straight away to reduce the risk of injury. If you respond quickly, it will have less of an impact.
Skin Contact
If fluid touches your skin, wash it off quickly with water and soap. Do not leave the liquid on the skin for a long time. If your skin becomes red, swollen, or irritated, see your doctor.
Eye Exposure
If fluid gets into your eyes, rinse them with water for at least 15 minutes. Keep an eye on them while they’re flushing. If the pain or blurred vision doesn’t go away, see your doctor quickly.
High-Pressure Injection Injury
If you think you may have been injured by high-pressure injection, go to the hospital straight away. Do not wait to get treatment. Even for minor wounds, say that high-pressure hydraulic fluid caused the injury.
Inhalation
If you breathe in oil mist, move to a place with good air circulation straight away. Try to breathe regularly. If the pain doesn’t go away, see your doctor.
FAQ
Is hydraulic oil toxic to humans?
Hydraulic fluids are not usually thought of as highly toxic substances, but they can be dangerous if you are exposed to them for a long time. Most mineral-based hydraulic fluids mainly cause skin or lung irritation, rather than immediate poisoning. You can find more information about the specific risks of using this product in the Safety Data Sheet (SDS).
Can hydraulic fluid cause cancer?
Hydraulic fluids are usually not considered to cause cancer when they are used normally. Risks are mostly linked to long-term exposure or certain additives. We need to know if there are any risks of cancer. This is based on the specific ingredients and occupational health standards.
What pressure can cause injection injury?
Injection injuries from hydraulic oil can occur at pressures of around 2000–5000 psi. Many industrial hydraulic systems work within this pressure range. Even small wounds can cause a lot of harm.
Is synthetic hydraulic fluid safer?
Synthetic hydraulic oils tend to be more stable at high temperatures than mineral-based oils, but this doesn’t mean they are necessarily safer. The risks to health and fire are still a problem, depending on how the product is made and how it is used. The type of oil you use should be based on the actual conditions you use it in.
How hot does hydraulic oil need to be to ignite?
Most mineral-based hydraulic fluids have flash points between 150–300°C (286–572°F). At or near these temperatures, oil vapours can catch fire. Auto-ignition points are higher, but you should still be careful in high-temperature environments.
Is hydraulic oil dangerous to the environment?
Leaks of hydraulic fluid can contaminate soil and water. Mineral-based fluids don’t break down quickly and last longer. The risks to the environment depend on how much liquid has leaked and how quickly it is cleaned up.
Can breathing hydraulic fumes make you sick?
If there is not enough air moving through the area, it can irritate the throat or cause coughing when you breathe in the hydraulic mist. The risk gets bigger the longer people are exposed to it, especially when there is a lot of the substance in the air.
Are biodegradable hydraulic fluids safer?
Biodegradable hydraulic fluids break down more quickly in the environment, but there are still some risks. They might still be dangerous or irritating. Their main advantage is that they have a smaller environmental impact if there is a leak.
Final Thoughts
Whether hydraulic fluid is dangerous depends on the pressure and temperature, and whether there is leakage or contact. If you understand these risks, you can reduce accidents and downtime.
Target Hydraulics has over ten years of experience in designing and using hydraulic systems. We offer high-pressure system optimisation, component selection and technical safety support. If you need professional advice, please contact us.
