At first it may appear that most commercial facilities are fairly safe. You’ll find OSHA-compliant safety signage, well-marked exits, clear pathways, adequate floor marking, and even a pretty good safety training program in place. But a silent killer lurks at every industrial and office facility, and every year, ignorance of its danger costs hundreds of workers their lives. In fact, industry’s systemic failure to address this hazard results in three of OSHA’s top 10 safety violations every year.

Electricity is the lifeblood that makes industry possible, powering everything from desk lamps to giant machines. Because it is so reliable and ubiquitous, workers—even trained electricians—often take it for granted. Electricity is an instant killer: One tenth of an amp of electricity traveling through a human being for only two seconds is enough to kill. Electrocution isn’t the only hazard, however. OSHA’s regulations concerning use and wiring of electricity are also designed to prevent fires that can result from faulty wiring.

The OSHA regulations related to electricity that most employers are cited for are 29 CFR 1910.147 (Lockout/Tagout), 29 CFR 1910.303 (Electrical General Requirements) and 29 CFR 1910.305 (Electrical Wiring Methods). Let’s put on our compliance officer’s hat and go over six typical electrical hazards. We bet that if you do a thorough review of your facility, you’ll find at least one problem to correct.

1. Extension Cord/Power Strip Issues

For starters, extension cords are meant for temporary use only. OSHA compliance officers commonly cite for this issue. “If it is obvious it has been there for an extended period of time they can cite it as temporary wiring in place of permanent,” said safety consultant Jonathan Brown, of Advanced Safety and Health in Louisville, KY. What’s the threshold between temporary and permanent? Ninety days, and only for temporary holiday décor such as lights. Here are some other extension cord issues:

• Damaged cords: Nicks, cracks, frays, and shorts can render a cord useless or worse, an electrocution hazard. Destroy damaged cords and purchase new ones. Running them through walls or across walkways damages them. Try stringing them overhead.

• Daisy-chaining extension cords and power strips: Plugging one extension cord or power strip into another reduces the wattage capacity of each cord and creates a fire hazard. Now that surge-protected power strips with cable lengths of 10-25 feet are commonly available, the need to daisy-chain is eliminated. If you need additional electricity, hire an electrician to install power outlets where they are needed.

2. Amateur Wiring/Grounding Issues

Electricity is simply too dangerous to trust to amateurs. Cutting off the grounding plug to a power or extension cord or splicing together a couple of cords might seem harmless, but doing so can have lethal consequences to an always-unsuspecting worker. Case in point: A Chinese immigrant restaurant owner and his wife were refurbishing their new restaurant, and he had replaced the electrical cord to a glass-fronted cooler by splicing a 10/2 wire to a one-foot length of extension cord plugged into a wall receptacle. He never saw the ground wire on the 10/2 cord come loose and when he contacted the metal frame of the cooler and an adjacent metal stove, he was electrocuted.

In another case, a 20-year-old lifeguard at a large apartment complex was electrocuted when he entered the pump house to adjust the chlorine pump. Tragically, the metal pump motor housing had become energized with 220 volts—it wasn’t grounded properly, and hadn’t been approved for wet locations such as the pump house.

3. Inaccurate Labeling

10 Tips for Safe Electricity

Always use a licensed, bonded electrician for any electrical work in your facility. If you have not tested your circuitry, have it analyzed for safety and thoroughly labeled. Treat all conductors as dangerous until they are locked and tagged out. Regularly inspect all electrical tools. Use ground fault circuit interrupters (GFCIs) and overcurrent protection devices. Review your electrical safety program. Avoid using ungrounded home appliances and overuse of extension cords in the office environment. Have fire extinguishers rated for electrical fires easily accessible. Use non-conductive ladders when doing electrical work. Never allow workers to do electrical work without the proper personal protective equipment (PPE).

It’s critical that electrical circuits are accurately labeled, and that switches, cabinets, arc flash hazards, etc. leave no room for confusion. How accurate and easy to read is the labeling on your facility’s electrical panels?

The story of a 32-year old maintenance worker illustrates this point: He had been asked to change a broken metal halide bulb in a ceiling fixture and had taken several precautions, including studying the “as-built” plans so that he could de-energize the circuit. However, the plans were not accurate and he was electrocuted when he used an uninsulated tool to remove the broken bulb. He had turned off a breaker, but it was mislabeled and the circuit was still energized.

Labeling switches and other components is critical too. A 43-year-old man testing the insulation on a conduit coil was electrocuted because of a faulty cable repair. However, a coworker was unable to de-energize the coil tester because the power switch was not labeled.

4. Openings in Electrical Enclosures

All the unused openings in an electrical panel have to be closed, including unused slots for breakers and knock-outs. If the opening isn’t replaced with a blank, a shock hazard exists if someone places a finger into an open slot.

5. Lack of Training and Electrical Safety Program

Nearly every electrocution or electrical burn suffered by workers could have been prevented had they been properly trained and followed standard operating procedures.

NFPA 70E (Article 110) and OSHA both spell out training requirements for electrical workers. The standards mandate that electrical workers are considered “qualified” when they know how to use a voltage detector and have specific knowledge and skills. According to these standards, employers must provide a documented electrical safety program that spells out safe work practices for employees. In addition, employees must be periodically retrained and the safety program audited for effectiveness.

6. Look! Up in the Sky!

Many electrocutions occur as a result of contacting overhead power lines. Whenever starting an electrical job, conduct a hazard analysis that takes into account location of nearby power lines. Poles, pipes, ladders, and other lengthy items held aloft are tall enough to convey a deadly jolt to a hapless worker.