Occupational Fatality Report 

Kentucky FACE Program 

Report No. 16KY039 Release Date: March 21, 2018 

Mechanic Struck and Killed by Over-Pressurized 

Suspension Air Spring on Tractor Trailer 

CASE SUMMARY 

On Thursday, August 4, 2016, a 50-year-old male 

mechanic (the victim) was in a pit changing a 

suspension air spring on a tractor-trailer cab when 

the over-pressurized air spring exploded and struck 

his forehead, instantly killing him. 

Recommendations for prevention: 

• Employers should enforce the use of 

manufacturer’s instructions and 

specifications when replacing suspension 

air springs. 

• Employers should develop and implement a training program for new employees and 

annual refresher training for those tasks deemed high hazard. 

• Employers should develop a formal written safety program and translate written training 

material into languages that all employees can understand. 

• Manufacturers should consider offering manuals and instructions in more than one 

language. 

EMPLOYER 

The employer is a tractor trailer/truck inspection and repair facility employing 20 people, and has 

been in operation since April 14, 1987. 

Figure 1. Left side air spring after the 

explosion. 

Kentucky Fatality Assessment and Control Evaluation (FACE) Program 
 

 

 

 

 

 

 

 

 

 

 

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EQUIPMENT 

Equipment involved includes Continental Conti-Tech Air Spring 9 10S-16 P 382 suspension air 

springs and a shop air pressure system. A Sterling L Series Tractor Trailer was the vehicle on 

which the air springs were being installed. 

Figure 2. Sample of a new air suspension air bag to Figure 3. The tractor-trailer the installation was 

be installed. taking place. 

SAFETY AND TRAINING PROGRAMS 

The company provided safety information to their employees by verbal instruction, weekly team 

meetings, training sessions, postings, and other written communication such as posters and 

handouts. They did not have a formal written safety program, and all training was provided in 

English only. Personal protective equipment was required; for this particular task, safety glasses 

were required. A progressive disciplinary action plan was in place for violations of safety rules. 

It is unknown if the victim had ever been disciplined for not wearing PPE, but his safety glasses 

were in his shirt pocket during the incident. Two employees, designated as first responders, had 

received formal training on first aid and CPR. 

The company had also purchased a Mitchell 1® Maintenance Manual computer software program 

that provided guidance on safe removal and installation of air springs. The software company 

was contacted about the availability of the software in other languages; they responded that the 

software program was available only in English. Interviews of the employees verified there was 

no formal training for installation of the air springs; training was provided on the job by fellow 

employees. None of the employees interviewed had utilized the available computer software 

training, and there were no written records to verify completion or review of the Mitchell 1® 

Maintenance Manual program. 
 

 

 

 

 

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VICTIM 

The victim was a 50-year-old foreign-born married father. The death certificate indicated that the 

decedent had completed 8th grade or less. He had been employed with the company since May 

27, 2014, as a full- time mechanic. 

INCIDENT SCENE 

The incident took place in a concrete pit, which was approximately 5 feet deep and 4 feet wide, 

and located in the floor of the building. This pit allowed access to the undercarriage of the trucks 

while allowing employees to remain in a standing position. Both mechanics, the victim and his 

coworker were working in this area when the incident occurred. 

Figure 4. View of the pit in which the 

victim was working at the time of the 

incident. 

Figure 5. View of the pit from above. 

WEATHER 

The temperature was approximately 76°F at the time of the incident. The humidity was 94%, and 

the wind was calm.

1 Weather was not considered a factor, since the facility was air-conditioned 

and the incident took place indoors. 

INVESTIGATION 

On Thursday, August 4, 2016, the Kentucky Fatality Assessment and Control Evaluation 

Program was made aware by Kentucky OSHA of a fatality involving a mechanic. A site visit 

and investigation were subsequently conducted. 

A semi-tractor was being serviced for installation of new suspension air springs. Air suspension 

is similar to a heavy-duty balloon that is filled with air supplied by a compressor on the vehicle. 
 

 

 

 

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When the vehicle carries a heavy load, sensors alert the air compressor to regulate the air 

pressure according to the change in weight. 

On Thursday morning, two mechanics were assigned to work in the pit under a Sterling L Series 

tractor removing and installing new suspension air springs, a task they had performed regularly 

for two and half years. During this process, two employees work for more than one hour per axle 

with 6 or more axles per vehicle, changing suspension air bags or springs up to five days a week. 

The two mechanics had a combined five years on-the-job experience at this assigned task. 

Figure 6. Air spring after the explosion. 

At approximately 9:00 am, the mechanics installed a new suspension air spring on the left 

forward rear axle of the vehicle’s tractor. They used the air from the shop air compressor to fill 

the air bag. The shop air compressor pressure was set to 175 psi. The vehicle air system on the 

truck that is normally used to fill the air springs is set to 120 psi. Using the vehicle air system is 

recommended in the manufacturer’s instruction on installation of air springs. 
 

 

 

 

 

 

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Instead of using a jack and jack stands to raise the axle, it was common practice for the 

employees to use the shop air system connected to the vehicle air system to raise the axle. 

As they were raising the left rear frame with the newly installed suspension air spring, the air 

spring exploded from the over pressurization, hitting the victim in the forehead. The victim’s 

safety glasses were in his pocket at the time of the explosion. 

Emergency medical services were immediately contacted, but the victim was pronounced dead at 

the scene by the coroner. 

CAUSE OF DEATH 

The cause of death was an open head injury. 

CONTRIBUTING FACTORS 

This investigation identified the following factors that contributed to the fatality: 

• Lack of safety training on installation and removal of air springs 

• Not following the manufacturer’s instruction for psi 

• Use of shop air compressor instead of truck’s air system 

• Failing to use jack stands to raise the axle 

RECOMMENDATIONS AND DISCUSSIONS 

Recommendation No. 1: Employers should enforce the use of manufacturer’s instructions 

and specifications when replacing suspension air springs. 

Manufacturer instruction states that jacks and chalks should always be used to secure a vehicle. 

The employees used the shop air compressor instead of jacks and jack stands to lift the tractor. 

The manufacturer also recommends no more than 100 psi for the air spring. The employees used 

the shop air compressor, which was set to a pressure of 175 psi. The truck’s air system was set 

to 120 psi; however, the truck is equipped with a computerized sensor that detects the volume of 

air needed, depending on the weight of the load. It fills the air spring and shuts off automatically 

when it has the correct volume of air. 

Installation Instructions of ContiTech Air Springs 2 (photographs not shown) 

1. Have your new air spring system ready. The best way to change an air spring is to use a 

complete system and to exchange axle wise. Please always refer to the mounting instructions 

of your vehicle manufacture. 

2. Deflate your air spring. Always secure your vehicle first and make sure it remains stable 

during the entire process. Deflate your air spring and keep the air pressure system and 

ignition completely switched off. Attention: the distance between chassis and ground will be 

reduced. 
 

 

 

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3. Loosen pneumatic valves. When loosening the valve from the air inlet make sure the 

compressor is still switched off. Remove air connection and make sure both the valve and 

the air pipe stay clean. 

4. Loosen all screws. First, loosen all screws connecting the air spring system to the chassis. 

Then loosen all screws connecting the air spring system to the axle. 

5. Preparation for installment of the new air spring. Remove the defect air spring system. 

Clean the faying surface and look for corrosion. Keep the air pipe closed against dirt or dust 

at all times. 

6. Inspect all other air springs on your vehicle. Check for abrasion, embrittlement and cracks 

in the rubber parts. Check metal parts for corrosion. Check plastic parts for capillary 

cracks. Check for possible contamination by lubricants such as oil, diesel, brake or cooling 

fluids. Remove all foreign objects such as stones or dirt. Remove all liquids and check 

source of contamination. 

7. Put your new air spring in place. Install the new air spring system between chassis and axle 

and insert screws (new ones if the old ones are corroded or the threads are worn down.) 

Tighten the top plate to the chassis first. Attention: make sure you use the correct torque, 

which is recommended by your vehicle manufacturer or the catalog. Leave the air inlet 

open. 

8. Tighten your new air spring. Pull down the piston until it touches the mounting plate (if 

necessary use the compressed air gun with max 0.3 bar). Compulsively comply with the 

height limit. Now tighten the piston to the axle with a torque key making sure to use the 

correct torque recommended by your vehicle manufacturer or in the catalogue. 

9. Inflate your new air spring system. Connect pneumatic valve with the air inlet of the new 

air spring also with the recommended torque. Inflate your air spring with the commended 

working pressure, release the safety catch of your vehicle and put it back into driving 

position. 

Recommendation No. 2: Employers should develop and implement a training program for 

new employees and annual refresher training for those tasks deemed high hazard. 

The mechanics had not been formally trained on the installation of the air springs; the only 

training provided was hands-on from other experienced employees. Employees should receive 

language and literacy appropriate targeted training on how to properly fill air springs, reducing 

the risk of over pressurizing by improper use of an air compressor. 

The employer had purchased the Mitchell 1® Maintenance Manual computer software that 

provided information on the safe removal and installation of the air springs; however, the 

software was offered in English only. Use of the manufacturer’s instructions or the use of the 

Mitchell 1® Maintenance Manual was not enforced. The victim’s proficiency in English is 

unknown. In the absence of translated written training material, an interpreter could have been 

provided to instruct any employee who may not have been able to understand written English, 

with hands on training conducted afterwards to ensure the employee understood the instructions. 
 

 

 

 

 

 

 

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Recommendation No. 3: Employers should develop a formal written safety program and 

translate written training material into languages that all employees can understand. 

The employer had 20 employees, and required personal protective equipment (PPE) be worn 

during certain tasks, including the task being performed at the time of the incident. According to 

OSHA 29 CFR 1910 Subpart I3

, any task or work situation that requires the use of eye, face, 

head, foot, or hand protection is required to have a written hazard assessment. A formal written 

safety program would have included the PPE requirement, and instructed employees on when the 

PPE was necessary, how to properly don, doff, adjust, and wear PPE, how to properly care for 

the PPE, and what the limitations of the PPE were. 

It is equally important to provide the written program, including the hazard assessment and PPE 

requirements, in a language that employees can read and understand since English was not every 

employee’s first language. According to a memorandum sent April 28, 2010 from David 

Michaels, Assistant Secretary for Occupational Safety and Health4, “... an employer must 

instruct its employees using both a language and vocabulary that the employees can understand. 

For example, if an employee does not speak or comprehend English, instruction must be 

provided in a language the employee can understand.” The training material should have been 

translated into languages that all employees could understand, and made available to employees 

upon request. 

Recommendation No. 4: Manufacturers should consider offering manuals and instructions 

in more than one language. 

The employer had several workers whose first language was not English, and it is unknown 

whether all employees could read in English. Providing manuals and instructions in a language 

that is familiar and easily understood removes the possibility of misunderstanding and avoiding 

safety risk issues. 

In 2015, The Washington Times reported that 21 percent of U.S. residents speak a language 

other than English at home.5 The article goes on to state that 25 million residents reported they 

speak English at levels they would rate as less than “very well”. The most commonly spoken 

language in American households other than English is Spanish, with more than 39 million 

residents speaking it in their homes, a rise of over 11 million when compared to 2001. This data 

shows a pressing need for foreign language instructions, and strongly suggests that 

manufacturers should consider providing information on how to safely operate their equipment 

in languages other than English, particularly in Spanish. 
 

 

 

 

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KEYWORDS 

Air springs 

Truck suspension systems 

Air pressure 

Workshop 

Over pressurizing 

REFERENCES 

1

“Historical Weather”. Archive. Weather Underground. https://www.wunderground.com/history 

2 Installation Instructions of ContiTech Air Springs. 

https://www.contitech.de/getattachment/bb52215f-b952-4d57-b0f8-

7e7c148eb964/AS_FL_Montage-en.pdf 

3 OSHA 29 CFR 1910.132 Subpart I “Personal Protective Equipment” 

https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=977 

7 

4 Memorandum For: Regional Administrators, OSHA Training Standards Policy 

https://www.osha.gov/dep/standards-policy-statement-memo-04-28-10.html 

5 Dinan, S. (2015, October 6). English isn’t main language at home for 21 percent in America. 

The Washington Times. Retrieved from 

https://www.washingtontimes.com/news/2015/oct/6/english-isnt-main-language-at-home-for-21-

in-ameri/ 

PHOTO CREDIT 

Photos are courtesy of Kentucky OSHA. 

ACKNOWLEDGEMENTS 

The Kentucky FACE program would like to thank the Kentucky OSHA, and the coroner for their 

assistance with this report. 

PROGRAM FUNDING 

The Kentucky Fatality Assessment & Control Evaluation Program (FACE) is funded by grant 

2U60OH008483-13 from the National Institute for Occupational Safety and Health (NIOSH). 

Please take the time to complete our brief survey regarding this report. 
 

 

 

 

 

 

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DISCLAIMER 

This case report was developed to draw the attention of employers and employees to a serious 

safety hazard and is based on preliminary data only. This publication does not represent final 

determinations regarding the nature of the incident, cause of the injury, or fault of employer, 

employee, or any party involved. 

This case report was developed by the Kentucky Fatality Assessment and 

Control Evaluation (FACE) Program. Kentucky FACE is a NIOSH-funded 

occupational fatality surveillance program with the goal of preventing fatal work 

injuries by studying the worker, the work environment, and the role of 

management, engineering, and behavioral changes in preventing future injuries. 

The FACE Program is located in the Kentucky Injury Prevention and Research 

Center (KIPRC). KIPRC is a bona fide agent for the Kentucky Department for 

Public Health. 

Email: kyfaceprogram@uky.edu | Telephone: 859-257-5839 

333 Waller Avenue Suite 242, Lexington, KY 40504 

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https://www.facebook.com/Kentucky-FACE-Program134135740092906/?view_public_for=134135740092906 

https://twitter.com/KYFACEProgram