The Last Line of Defense

Understanding the PPE focus in OSHA’s arc flash guidance.

• By David Kopf
• Jun 30, 2025

Electrical injuries are among the most severe hazards in the workplace, and arc flashes represent one of the most violent types of electrical incidents. These electrical explosions produce blinding heat that can exceed 35,000 degrees Fahrenheit, along with concussive blasts and shrapnel made of molten metal. Most arc flash injuries result not from the arc itself, but from flammable clothing igniting on the worker’s body. That makes PPE not just important—but often life-saving. 

Recognizing this, OSHA issued updated arc flash guidance in late 2024, marking its first significant update in nearly 20 years. While not a new standard, the guidance reaffirms existing requirements and highlights the primary sources of confusion and non-compliance. According to OSHA, more than 600,000 American workers are exposed to arc flash hazards without the protection they need. The guidance aims to change that. 

The new guidance is built around five main themes: hazard identification and assessment; worker participation; hazard prevention and control; understanding approach boundaries; and personal protective equipment. While each component is vital to a comprehensive safety program, the PPE portion deserves special attention—both because it’s often misunderstood and because it’s frequently the last line of defense when all else fails. 

A Paradigm Shift 

As Scott Margolin, Vice President of Technical at Tyndale and Chairman of the Partnership for Electrical Safety, told OH&S’s SafetyPod podcast earlier this year (listen to Episode 216), the arc flash PPE conversation has undergone a paradigm shift. Historically, workers might have assumed they didn’t need PPE unless someone could prove otherwise. The new posture is the opposite: PPE is required unless and until it can be proven otherwise. 

That shift is rooted in persistent misunderstandings. For example, many workers mistakenly believe low-voltage systems (120/208V or 277V) pose minimal risk. Others claim they only work on deenergized equipment, despite all the steps to get to a deenergized state require wearing PPE. But OSHA estimates that more than 90 percent of workers who think they’re working on deenergized systems haven’t met the full standard for deenergization under OSHA’s lockout/tagout requirements. In short, they should still be wearing PPE. 

What the Guidance Says About PPE 

The updated OSHA guidance emphasizes that PPE must not be seen as optional. It breaks PPE down into several key categories: 

• Arc-Rated (AR) Clothing: Clothing that resists ignition and insulates the body from arc flash heat. Workers must be covered from wrist to ankle to neck with arc-rated garments. The wrong shirt can mean the difference between walking away and life-threatening burns. 

• Undergarments Matter: OSHA and industry experts stress that meltable or flammable undergarments (like polyester) can ignite even beneath AR outerwear. Additionally, incorrect wear—such as rolled sleeves or untucked shirts—can expose workers to injury. PPE must be worn correctly and completely. 

• Rubber Insulating Gloves and Leather Protectors: Gloves are essential for shock protection. Leather protectors go over rubber gloves to prevent punctures and wear. 

• Face Shields, Safety Glasses, and Hard Hats: These protect the head, eyes, and face from blast pressure and debris. OSHA emphasizes that face shields should be arc-rated and worn in conjunction with safety glasses. 

• Hearing Protection and Footwear: Arc flashes are loud enough to cause hearing loss. Proper footwear, such as EH-rated boots, protects against step potential and provides additional insulation. 

OSHA aligns its PPE categories with the NFPA 70E standard, which outlines four levels based on arc flash incident energy: 

• Category 1 (4 cal/cm²): Basic AR shirt and pants, safety glasses, hearing protection. 

• Category 2 (8 cal/cm²): Adds balaclava or flash hood, arc-rated face protection, gloves. 

• Category 3 (25 cal/cm²): Full flash suit jacket and pants, multi-layer PPE. 

• Category 4 (40 cal/cm²): Highest protection—head-to-toe flash suit with full gear. 

Each level corresponds to increasing risk and prescribes specific PPE to match the hazard. 

Why PPE Still Gets Overlooked 

In many environments, especially construction and maintenance, PPE compliance lags. For example, Margolin points out that both seasoned electricians (who may become complacent) and new workers (who may not know better) can be at elevated risk. This is compounded by outdated assumptions about what qualifies as energized work, and by economic or logistical hesitations to provide proper gear. 

Yet OSHA’s updated materials make it clear: if work involves potential exposure to energized electrical conductors above 50 volts, PPE is required unless a full lockout/tagout process has been completed and verified. Even testing for the absence of voltage requires full PPE. 

Final Thoughts 

The core message of OSHA’s arc flash guidance is not just technical—it’s cultural. Arc-rated PPE isn't just a compliance issue; it's the one thing standing between a mistake and a fatality. Employers need to reinforce training, correct misunderstandings, and make PPE an uncompromised standard. 

With expanded EV infrastructure, grid upgrades, and new electrical maintenance standards, workers are encountering electrical hazards more frequently and at higher risk. PPE may be the last line of defense, but with OSHA's renewed focus, it doesn't have to be the forgotten one. 

This article originally appeared in the June 2025 issue of Occupational Health & Safety.