Joseph Hrinik: Hydraulic Fluid Hazards

Safety First
- 23 Aug 2007 ( #324 )
6 min read
Joseph Hrinik lives in Michigan (USA) where he retired after 40 years of diversified occupational health and safety experience in both the private and public sectors. He is currently researching regional and national forklift safety legislation and forklift training programs.
Hydraulic fluid used in high pressure hydraulic systems poses several health and safety hazards. All parties exposed to high pressure hydraulic equipment (including forklift operators) must be informed of the hazards and the appropriate safeguards for hydraulic fluids and high pressure hydraulic systems.

Some Material Safety Data Sheets (MSDS's) adequately warn of some of these hazards. Many do not. Here are a few of these hazards.

Injection under the skin:

Hydraulic fluids usually operate at a pressure that can readily inject leaking fluid through the skin and deep into the soft tissue. The injection might be painless. The injection site, however, can ultimately become very painful. Untreated injection type injuries threaten both life and limb.

Immediate medical attention is required after injection. Surgical debridement is usually required. Not all medical facilities are capable of providing this medical service. An emergency medical facility that is aware of the seriousness of such an injury - and is capable of providing the proper medical treatment - should be located prior to the emergency. The appropriate emergency medical treatment facility for injection type injuries should be spelled out in your emergency procedures. If you have a remote operation where such medical treatment is not readily available, you should preplan for medical evacuation by air.

ExxonMobil provides warning of this hazard on their (Mobile Hydraulic Oil 15 Special) Material Safety Data Sheet: "If product is injected into or under the skin, or into any part of the body, regardless of the appearance of the wound or its size, the individual should be evaluated immediately by a physician as a surgical emergency. Even though initial symptoms from high pressure injection may be minimal or absent, early surgical treatment within the first few hours may significantly reduce the ultimate extent of injury." Other MSDSs may not provide such detailed information.

Never use hands or fingers to search for hydraulic leaks. Gloves do not offer adequate protection from this injection hazard.

Industrial safety glasses with side shields should be the minimal eye protection when working on hydraulic systems or performing forklift pre-shift/post-shift inspections.

Burns and injuries from fire/explosion:

Most common petroleum-based hydraulic fluids will burn. Hydraulic fluid becomes heated during normal operations to fairly high temperatures. This preheated hydraulic fluid, if exposed to air in the presence of an ignition source (spark/flame), could ignite if it is heated to its ignition temperature. It could also ignite if heated by any thermal source (manifolds, hot surfaces, hot environments, etc.) which raises the hydraulic fluid to its rated auto-ignition temperature.

In atomised form, such as a high-pressure pinhole leak, hydraulic fluid can readily be ignited, causing a flash fire with a substantial fireball. If the atomised fluid is enclosed within a confined area with sufficient oxygen, an explosion could occur should it become ignited.

Radiated heat and direct flame contact can cause serious thermal burn injuries. Exploding mixtures can add shock wave and projectile injuries.

Portable fire extinguishers are recommended on forklifts. In some locales they may be required. They are only effective if the operator and other personnel are trained in their proper operation. Portable fire extinguishers must be properly maintained.

Automatic fire suppression systems are available for mobile equipment. Such systems may be appropriate for certain equipment.

Fire-resistant hydraulic fluids are available for use with some types of equipment. Consult with your forklift manufacturer before specifying or substituting these fluids.

Thermal burns from contact:

Physical contact with hydraulic fluid or certain hydraulic components at normal operating temperatures can cause serious burns. Contact with the actual fluid will usually cause more severe burns than contact with the enclosures as the hot liquid will remain on the skin, until it cools or is removed from the skin surface, increasing the length of thermal contact. Immediate release from physical contact of enclosures (cylinder, hose, line, fitting, etc.) lessens the thermal impact but can still cause serious injury.

Operator training should include familiarity with high temperature component locations.

Injuries from loose hydraulic hoses:

Due to the high pressure within a hydraulic system, the impact force of a disconnected and flailing hydraulic hose can cause abrasions, concussions, contusions, fractures and lacerations. Proper maintenance and good pre-shift equipment inspections can minimize this hazard.

Injuries from opening a pressurized hydraulic system:

Failure to de-energise (using proper lockout procedures) the hydraulic pressure system prior to opening the pressurised system can cause a person to fall or be struck by flying parts or pressurised fluid. It can also create shear point and pinch point hazards due to the potential for moving parts once pressure is released. Written lockout/tagout procedures should be established and personnel trained in these procedures. If the service manual does not address this issue, check with the manufacturer to ensure that high pressure fluid systems can be safely de-energised prior to maintenance activities.

Injuries from slip hazards:

Hydraulic fluids are slippery. A person can slip and fall from a spill on the floor, a spill on the equipment steps or from hydraulic oil residue on the soles of the shoes. Spills or contamination should be cleaned up immediately.

Three-point contact should be required for entry into and exit from the operator compartment.

Injuries from grip hazards:

Hydraulic fluid on the hands can cause a person to lose grip while climbing into or out of the operator compartment. It can cause the operator to lose steering control due to a slippery steering wheel. It can cause an operator to drop a part of the load being manually handled (stock-picking, etc.). Operator's hands/gloves should be free from any contamination that could affect proper grip.

Material incompatibility hazards:

Petroleum-based hydraulic fluids are not compatible with oxidizers. Fire/explosion can occur. Handle and store properly.

The above hazards can cause serious injury or death and must be taken seriously!

Lesser Health Hazards:

Petroleum-based hydraulic fluids are skin and eye irritants and are also slightly toxic. Wash contaminated skin and keep clothing free of fluid contamination. If there is eye contact, flush eyes thoroughly with water. Seek medical attention if irritation persists. Personnel should not eat, drink, or smoke when hands are contaminated.

This article is introductory in nature and does not cover all hazards or safeguards. Readers will have to do further research based on their equipment and exposures. More detailed information on some of the hazards and safeguards can be found in the following links:
This report is a must read as it focuses on skin injection hazards and the proper method to inspect hydraulic lines. It stresses the seriousness of a skin injection injury. It also addresses other hazards.
NIOSH released this in-house report (2006-05 - Tennessee) in July 2007. It summarizes a petroleum-based hydraulic fuel fire that engulfed the operator compartment of a bulldozer. The operator eventually died from the burns and the trauma he received. Although this fatality report centers on a bulldozer fire, it could have readily happened on a forklift. The hazard information is applicable.
Select In-House Reports. Select In-house Reports 2000-2007. Select 2006-05 Equipment Operator Dies From Burns ...Tennessee.
The Fluid Power Safety Institute (USA) is dedicated to reducing fluid power accidents. Safety Alert #01 is not specific to forklifts but the information is applicable. It also has a very graphic picture of surgical debridement. Select Fluid Power Safety Institute™. Click on Safety Alerts at the top of the page. Click on the text description for SA-001. You can also read several other fluid power safety alerts on this site.
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