Machine Guarding Expert Witness

Overview

About Machine Guarding Expert Witnesses

A machine guarding expert answers one question: should this person's hand have been able to reach that part of the machine while it could move? Nearly every other issue in the case follows from the answer, including whether a guard was needed, whether the one supplied was adequate, who removed it, and whether the machine should have been shut down and locked out before the work began.

The federal baseline is short and broad. Under 29 CFR 1910.212, one or more methods of guarding must protect the operator and other employees in the machine area from hazards such as the point of operation, ingoing nip points, rotating parts, and flying chips and sparks ¹. The point of operation is the area on a machine where work is actually performed on the material, and on any machine whose operation exposes an employee to injury it shall be guarded ¹. Where no specific standard applies, the guard must be designed to prevent the operator from having any part of the body in the danger zone during the operating cycle ¹. That performance language is why these cases need an expert: the rule says what the guard must do, not what it must look like.

Which Standard Governs

The first task is to identify the machine and the activity, because each points to a different rule. Machines that usually need point-of-operation guarding, according to the regulation's own list, include guillotine cutters, shears, power presses, milling machines, power saws, jointers, portable power tools, and forming rolls and calenders ¹. Beyond that list:

• Mechanical power presses have their own detailed standard at 29 CFR 1910.217, which also requires an inspection program with a general and a directed component and certification records of inspection, maintenance and repair ³
• Belts, pulleys, gears and shafts are addressed by the mechanical power-transmission rule at 29 CFR 1910.219 ⁴
• Servicing and maintenance falls under the lockout/tagout rule at 29 CFR 1910.147, which covers work where unexpected energization, start up, or release of stored energy could cause injury ²

Both the machine guarding and the lockout/tagout rules appear on OSHA's preliminary list of the top 10 most frequently cited standards for fiscal year 2026 ⁵.

Production or Servicing

The most contested line in many of these cases separates the two rules. Guarding protects people during production. Lockout/tagout protects them during servicing, which the standard defines to include setting up, adjusting, inspecting, and the lubrication, cleaning or unjamming of machines ². Injuries cluster on that border. OSHA's amputation guide describes employees hurt while setting up machines, bypassing guards to clear jams or lubricate parts, and inspecting or adjusting machine parts ⁶.

There is a narrow exception. Minor tool changes, adjustments and other minor servicing during normal production are outside the lockout rule only if they are routine, repetitive, and integral to the use of the equipment, and only if alternative measures provide effective protection ². Whether a recurring jam-clearing task qualifies is often the center of the dispute. An expert reads the employer's procedures, the machine's manual, and the production records to establish how often the task occurred and what protection was really in use. The rule also requires a periodic inspection of energy control procedures at least annually, so the absence of those records can be evidence in itself ².

Guards, Devices and Warnings

Not every safeguard counts equally. OSHA's guide draws on the ANSI B11.19 safeguarding standard and states that devices that detect, but do not prevent, employee exposure to machine hazards are not considered primary safeguarding methods ⁶. Awareness devices, such as a barrier, signal or sign, warn of a hazard without stopping contact ⁶. A warning label on an unguarded nip point is therefore a weak answer to a guarding claim, and the expert will explain why.

The expert also tests whether a guard was feasible and whether it could be defeated. The analysis covers what guards and devices were available when the machine was built, what the job required of the operator, whether the guard made the task slower or harder, and whether an interlock could be bypassed with a simple tool.

Who Is Qualified, and Who Does What

No single license defines this field. The strongest witnesses are mechanical or safety engineers with direct experience designing, safeguarding, or auditing the type of machine in the case, and many hold a professional engineering license or a safety credential. Match the witness to the defendant. In a product claim against the manufacturer, a machine design engineer addresses alternative designs and foreseeable use. In a claim about plant practices, a safety engineer or industrial hygienist addresses training, procedures, and supervision. OSHA standards bind employers, and the Act states that it does not enlarge, diminish, or affect common law or statutory rights and liabilities of employers and employees for workplace injuries, and does not affect workers' compensation law ⁷. How a citation or a standard may be used at trial therefore varies by state, and counsel should address it directly with the expert before disclosure.

Qualifications

Qualifications to Look For

• ✓Degree in mechanical, industrial, or safety engineering, with a professional engineering license where the opinion concerns design
• ✓Direct experience designing, safeguarding, or auditing the type of machine at issue
• ✓Working command of 29 CFR 1910 Subpart O and the lockout/tagout standard at 29 CFR 1910.147
• ✓Familiarity with the ANSI B11 series of machine safety standards in force when the machine was built and when it was used
• ✓Experience conducting risk assessments and task-based hazard analyses on production equipment
• ✓Ability to inspect the machine, test interlocks and safety devices, and document the condition found
• ✓Prior deposition and trial testimony experience in machinery injury litigation

FAQ

Frequently Asked Questions