Safe Bolt Loosening: Best Practices for EHS Managers

Improper bolt loosening can lead to serious injuries and workplace hazards.

• By Olga Bodiagina
• Mar 19, 2025

Maintenance and repair tasks, including bolt loosening, pose significant safety risks if not performed correctly. According to the U.S. Bureau of Labor Statistics (BLS), in 2020, there were 23,400 nonfatal injuries and illnesses requiring days away from work among general maintenance and repair workers in private industry, with an incidence rate of 241.9 per 10,000 full-time equivalent (FTE) workers. https://www.bls.gov/iif/snapshots/osn-maintenance-and-repair-workers-general-2016-20.htm

Bolts are essential fasteners used across all industrial sectors, including manufacturing, construction, energy, and transportation. Studies on maintenance efficiency show that "wrench time"—the actual time spent performing physical work—accounts for 25% to 50% of a maintenance worker’s shift. https://www.reliableplant.com/Read/32402/facts-about-maintenance-wrench-time A significant portion of this time is spent on disassembling and reassembling equipment, making bolt loosening one of the most common yet potentially hazardous tasks in industrial operations.

Although bolt loosening may seem routine, it carries serious risks if not executed properly. Improper techniques, inadequate tools, or a lack of safety precautions can lead to injuries such as hand and wrist strain, loss of balance, and even severe falls. In high-risk environments, even a minor misstep can result in significant workplace incidents.

For example, during a major shutdown, a contractor was assigned mechanical work involving bolt loosening. As he applied force to a stubborn bolt, his wrench slipped, causing a sudden loss of resistance. The unexpected movement led him to stumble and fall, resulting in a rib injury after colliding with previously dismantled equipment. This incident highlights the importance of proper technique, the right tools, and risk awareness when performing seemingly simple maintenance tasks.

Another incident involved a clogged sludge line that required maintenance intervention. A duty crew received a task to remove an insert in the primary sludge supply pipeline. While unbolting a flange connection, a bolt jammed. Due to limited workspace, one worker held the nut with a wrench while the other attempted to unscrew the bolt. When additional force was applied, the wrench slipped off, causing the mechanic's hand to strike a nearby pipe, resulting in a laceration injury.

To prevent such incidents, EHS managers must ensure that workers follow the correct techniques and safety precautions when loosening bolts, particularly those that are corroded, over-tightened, or located in confined spaces.

Several factors can complicate bolt loosening, including:

• Corrosion – Rust can create strong bonds between bolt threads, making them resistant to movement.
• Thread Galling (Seizing) – Friction between metal surfaces can cause material transfer, fusing the bolt and nut together.
• Over-Tightening – Excessive torque can cause threads to stretch, making bolts difficult to loosen.
• Damaged Bolt Heads – Stripped or rounded bolt heads reduce tool grip and complicate removal.
• Limited Accessibility – Tight spaces can prevent proper tool positioning and leverage.

To enhance safety and efficiency, EHS managers should ensure workers use the appropriate methods based on the specific challenge encountered. The hierarchy of safer methods should always be followed, starting with the least force-intensive approach:

Addressing Corrosion and Rust (First Choice Before Force Methods):

• Apply penetrating oil (WD-40) and allow it to soak for 10–15 minutes before attempting to loosen the bolt.
• Clean rust from bolt surfaces using a wire brush.
• Utilize the thermal method by heating the bolt with a heat gun or torch (ensuring no flammable materials are nearby).

Ensuring Proper Tool Use (When Initial Methods Fail):

• Box-end wrenches or socket wrenches provide better grip than open-end wrenches.
• Tubular wrenches are useful for bolts in recessed areas.
• Impact wrenches should be used with caution, ensuring correct torque settings. (OSHA 29 CFR 1910.242 – Hand and Portable Powered Tools)
• Breaker bars or extension pipes can be used to increase leverage but should be properly secured to prevent slipping.

Handling Thread Galling:

• Apply lubricants specifically designed for metal surfaces.
• Work the bolt back and forth instead of forcing continuous counterclockwise motion.

Managing Limited Access and Visibility:

• Use mirrors and proper lighting to inspect bolts in difficult-to-see areas.
• Select appropriate angled wrenches or extension tools to maintain ergonomic positioning.

Safe Techniques for Removing Damaged or Stuck Bolts (Last Resort Methods):

• If the bolt head is rounded, weld a nut onto the bolt to create a new gripping surface.
• Use a bolt extractor to grip and remove stripped bolts.
• In extreme cases, cut the bolt with a grinder and drill it out.

Regardless of the method used, EHS managers should enforce the following safety measures:

• Personal Protective Equipment (PPE): Require safety gloves (preferably split leather for hand protection) and eye protection when using mechanical tools or penetrating oils. (OSHA 29 CFR 1910.132 – General Requirements for PPE)
• Thermal Methods: Prohibit heating methods near flammable materials and ensure adequate ventilation. (OSHA 29 CFR 1910.252)
• Hand Tool Safety: Ensure workers have stable footing when using impact or breaker bars to prevent sudden loss of balance. (OSHA 29 CFR 1910.242)
• Power Tool Precautions: Require face shields and hearing protection for workers using grinders or drills, and ensure compliance with hot work permits if required. (OSHA 29 CFR 1910.215 – Abrasive Wheel Machinery)
• Chemical Safety Compliance: When using penetrating oils (WD-40) or solvents, workers should follow HAZCOM procedures, including reading Safety Data Sheets (SDS) and ensuring proper ventilation. Labeling and proper storage of chemical products must also be maintained. (OSHA 29 CFR 1910.1200)
• Hot Work Safety: If using heat guns or torches, workers should follow hot work permit procedures. Fire watch personnel should be assigned when necessary, and fire extinguishers must be accessible. (OSHA 29 CFR 1910.252)

While cutting a bolt is generally considered a last resort due to the additional safety measures required, there are cases where it is the safest option. If workspace constraints prevent the use of standard tools or if a bolt is severely corroded and unlikely to loosen safely, cutting it immediately can reduce overall risk. In such situations, workers should follow proper safety protocols, including the use of protective equipment and hot work permits, to ensure the task is performed safely and efficiently.

While the methods I described help reduce risks during bolt loosening, the most effective way to protect workers is to prevent bolt seizing in the first place.

Preventing issues with bolt loosening starts with proper selection, installation, and maintenance practices. EHS managers should implement proactive strategies to reduce risks and minimize the need for forceful removal methods. Key preventative measures include:

• Proper Bolt Selection – Choose corrosion-resistant materials such as stainless steel or coated fasteners for environments prone to rust.
• Thread Lubrication – Apply anti-seize compounds or lubricants during installation to prevent galling and corrosion buildup.
• Torque Control – Use torque wrenches to apply proper tightening force, reducing the likelihood of over-tightening or seizing.
• Routine Inspections – Establish regular maintenance schedules to check for early signs of corrosion or thread damage.
• Environmental Protection – Where possible, shield bolts from moisture, chemicals, and extreme temperature changes to prevent premature deterioration.

Loosening bolts may seem like a simple task, but if done incorrectly, it can lead to serious injuries. Workers may suffer hand injuries, lose balance, or even fall. EHS managers play a crucial role in communicating these risks and ensuring employees understand the safest ways to perform this task. Providing clear instructions, hands-on training, and regular safety reminders can help reinforce best practices.

The best way to prevent injuries is to stop bolts from seizing in the first place. Selecting the right bolts, applying lubricants, tightening them to the correct torque, and conducting regular inspections can prevent many issues. EHS managers should emphasize proactive maintenance to reduce the need for forceful removal and improve workplace safety.

By fostering a strong safety culture and ensuring all workers follow these best practices, EHS managers can help prevent injuries and maintain efficient operations.