Your UPS battery backup may be killing you

Sulfur odor from a UPS battery back up is dangerous to your health

By Stephen Pate – Using a UPS batter backup for your office or home office computer comes with the health risks from exposure to hydrogen sulfide and sulfur gas.

Ignoring the risk can cause throat irritation, headaches and even death. In my case it gave me a sore throat that led to the worst cold in years.

From power outage to me outage

I’d been using battery powered interruptibility power supplies (UPS) at work for decades. I thought nothing of  buying a new one two weeks ago.

I hooked it up and Windows 7 immediately recognized it as a UPS and added a monitoring icon in the tray. Within only one day, we had a power spike and dropout that killed everything but my desktop. It seemed like a wise purchase.

Buy – CyberPower CP1350PFCLCD PFC Sinewave UPS 1350VA 810W PFC Compatible Mini-Tower

Since I wrote this, better UPS backups have come on the market without this problem. Try Amazon.com for top rated UPS battery backups.

I noticed a sharp sulfuric acid smell that grew stronger each day. It wasn’t the rotten egg smell. It was sulfuric acid. I checked the UPS, which uses sealed lead-acid batteries. They weren’t leaking. I emailed APC the manufacturer of the UPS.

“I installed an XS900 ups backup one week ago. There was a smell of sulfur immediately on taking the ups out of the box. I thought is was the new cardboard smell. It has been getting stronger every day. Today my throat is raw and the air in my office is pungent.  Is this normal for the unit to vaporize odors?  What is the solution?”

In the meantime, I got a pounding headache, my throat went from raw to sealed shut. I took the initiative and moved the UPS out of my office to the garage. Then I put myself to bed. I was sick. My fever went to 102 before it broke. I still have a hacking cough and hope to be better soon.

APC responds

The next day APC replied with 9 questions but no recommendation to remove the UPS from the work area.

According to their bulletin, the issue is with “rotten egg” odors.

Hydrogen Sulfide Gas
People sometime complain of a bad, “rotten egg” smell or tingling of the nose after a thermal event. That is most likely caused by hydrogen sulfide (H2S ) gas. Darkening of copper battery terminals is also an indication of H2S . Thermal runaway does not always expel H2S. The exact mechanism is unknown. H2S is
common in nature, frequently as a result of rotting vegetation or animal manure. The human nose can detect H2S at levels as low as 0.005 to 0.02 parts per million (ppm). The Illinois Dept. of Public Health describes that as “the same as a thimble full of hydrogen sulfide gas in a theater full of air. 7 The National
Institute of Environmental Health Sciences says H2S can be detected at about 1/400 of the threshold for harmful human effects. The US Government says that 20 ppm is the acceptable ceiling for daily 8-hour exposure. 8 OSHA allows a maximum 50 ppm for 10 minutes acceptable maximum peak above the normal  ceiling.

While there is some evidence of risk from long-term exposure to H2S, there is no evidence of risk from short-term, moderate levels of exposure. Symptoms of exposure include eye, nose and throat irritation, and sometimes headaches. At extreme concentrations serious illness or death can result. For exposures below 250 ppm, recovery occurs quickly if exposure to H2S is brief, and there should be no long-lasting effects.

Because the amount of H2S given off during a VRLA thermal event is so tiny, the risk is usually insignificant. H2S can be detected well before it is harmful. However, when H2S is detected it is prudent to ventilate the room and/or exit the area. APC

There are generic warnings in other bulletins about venting.

Use of a battery powered UPS in a home or small office setting may not be health wise. The UPS went back yesterday to Staples which was my first time outside in 8 days.

Follow me on Twitter at @sdpate or on Facebook at NJN Network and OyeTimes.

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  • Alejandr0

    You are not imagining things. Something is wrong with one of the batteries in your UPS. The smell you are describing is indeed H2SO4. I know the smell of Hydrogen Sulfide. It smells like rotten eggs. I also know the smell of Sulfuric Acid vapors (I minored in Chemistry). H2SO4 vapors have a very pungent, tangy odor that irritates the nose much like wasabi. We had a very large, multi-battery UPS delivered for a LAN closet at our corporate office call center build out. The UPS weighed over 1K lbs. Within 24 hours of turn-up, I found the fumes in the LAN closet to be unbearable. My coworkers did not notice any smell. By the end of the first week, I could easily smell the H2SO4 fumes down the hallway. Still, my boss and coworkers couldn’t smell anything. By the end of the first month, the UPS began failing self diagnostics. Because of its youth, the vendor did a full swap instead of repair. The new unit did not emit any odor. I have 12+ years in enterprise IT. If the UPS smells of H2S04, the batteries need to be replaced…no discussion.

  • http://agarcia.tv/ Aaron

    Thanks for sharing this. I’ve been smelling this odor since they sent me a replacement to another unit that started smoking a black substance. This new one wakes me up at night and I thought I was imagining things. It’s happened several times, now. I know it’s real. I hope no damage was done to my health.

  • http://designbuddy.com/ DK

    Interesting. I’ve noticed that my office has always had a very strong burnt plastic odor, but figured this was just a result of having many computers, printers, external hard drives, modems, and so on. Though I’ve been noticing the chemical smell growing stronger the past year or so. I’ve also noticed that I seem to get a lot more headaches and sore throats. My wife even mentioned this odor.

    I see that the odor you experienced was more of a sulfur smell though. Does anyone know if it’s normal for a UPS battery to have a somewhat strong chemical smell similar to that of a new electronic device after unpacking? The issue is that this smell doesn’t dissipate after a couple of days.

    My UPS is an APC model Back-UPS XS 1000. It’s about 5 years old, but still works flawlessly and appears to have a strong battery. I’d hate to get rid of it and drop more money on a new one if this still works fine. Do they all smell like this? I’m guessing it always smelled and I just noticed recently. Any feedback would be appreciated. Thanks.


    Hmm. Yeah this is why you should discard rather than reuse VRLAs from UPS’s. Also they aren’t very useful as they tend to internally short after so many years resulting in a doorstop.
    I also found that adding chlorine (either salt or impure water) to flooded batteries REALLY is a bad idea, the nice guy at Lucas mentioned that one as a particular issue when a battery room in a sub or on a boat is flooded.