Smell of rotten eggs in the server room

Question

A week ago I got the following error on my APC Smart-UPS 1000 which I muted.

Warning State:
Connect battery
Load: 55%
Batt: 100%

Today, I could smell a sort of sulfur/sulphur/rotten egg smell when I came into the office and the UPS is alarming again. There isn't a burning smell.

I have vented the office & server room and shutdown the UPS.

Got any other advice?

UPDATE: This is what I found in the UPS.

Solution 1

To answer the question: This is almost always a lead-acid battery failure causing the battery to vent hydrogen sulfide (H₂S). The battery needs to be replaced as soon as possible.

As an additional note, H₂S can be extremely dangerous at higher concentrations. If you experience eye irritation or difficulty breathing or your ability to smell the odor deteriorates noticeably, the concentration of the gas is dangerously high and you should see a doctor. At that point, you may need to hire a hazmat cleanup service to remove the battery and clean up the area.

Wikipedia says this on H₂S toxicity:

• 0.00047 ppm or 0.47 ppb is the odor threshold, the point at which 50% of a human panel can detect the presence of an odor without being able to identify it.
• 10 ppm is the OSHA permissible exposure limit (PEL) (8 hour time-weighted average).
• 10–20 ppm is the borderline concentration for eye irritation.
• 20 ppm is the acceptable ceiling concentration established by OSHA.
• 50 ppm is the acceptable maximum peak above the ceiling concentration for an 8-hour shift, with a maximum duration of 10 minutes.
• 50–100 ppm leads to eye damage.
• At 100–150 ppm the olfactory nerve is paralyzed after a few inhalations, and the sense of smell disappears, often together with awareness of danger.
• 320–530 ppm leads to pulmonary edema with the possibility of death.
• 530–1000 ppm causes strong stimulation of the central nervous system and rapid breathing, leading to loss of breathing.
• 800 ppm is the lethal concentration for 50% of humans for 5 minutes exposure (LC50).
• Concentrations over 1000 ppm cause immediate collapse with loss of breathing, even after inhalation of a single breath.

Solution 2

It sounds like one of your lead-acid batteries has gone bad and is now leaking hydrogen sulfide (H2S) into the air.

You will obviously want to replace the battery, but I would think some cleaning may also be in order as both hydrogen sulfide and the sulfuric acid normally present in the battery are corrosive. (Do consider that hydrogen sulfide is also toxic.)

Comments

[Andy Joiner]

Note to self: Always configure the remote management if your UPS supports it. It's not nice being the one to go in and press the power button.

[MDMoore313]

Possible duplicate of Something is burning in the server room; how can I quickly identify what it is?

[bwDraco]

@BigHomie: This is a special case. I wouldn't vote to close as duplicate because this is a potentially dangerous condition that should be treated on its own. It's also not really a burning, fire, or overheating scenario more than it is a battery chemical failure. Lumping the two questions together could confuse readers.

[MDMoore313]

Fair enough @bwDraco, couldn't the older question be treated as: There is a bad smell in the server room; how can I quickly identify what it is type of scenario, though? I will say this question might have enough merit to stand on it's own, and the votes will indicate that.

[Sirex]

generally given the dangerous nature of them (fires, lead acid leaks, etc) i'd be very wary of muting any alert from a UPS unit.

[Criggie]

UPS batteries have a limited life - anything from 2 years in a budget UPS up to 5-7 years in a good quality UPS like your APC. I bet the batteries are End Of Life and they were last replaced 7 years ago. Buy four new batteries of the same spec and swap them out. You should inspect for any corrosion, but the UPS is probably okay. And schedule another battery replacement in 2022. Write on the case the date of last battery change.

[wizzwizz4]

Maybe the error should be replaced with "Battery on fire"

[Xen2050]

That's also the smell of a leaking gas line in the building... but I'd expect that a server room has plenty of ignition points, so if it were a gas leak it probably would have exploded already

[Harpic]

I recently had two good quality sealed lead acid (SLA) batteries in an server APC rack mounted UPS overheat and noticed it because of a bad frying plastic smell. They were too hot to touch for hours afterwards. There was only one warning alarm which could be cancelled. I also assumed there was a protection circuit against overheating, it did not work. H2S is as toxic than Hydrogen Cyanide but more easily detected by its strong nasty smell. At high concentrations the smell cannot be detected. Be cautious if you do smell it.

[mckenzm]

If it is not a battery if may be a capacitor rupture, these can have a strong smell too, but generally cause a more catastrophic failure.

[Lolums]

Rotten eggs is the smell of sulfur dixoide.

[underscore_d]

Rather than appending an update, since answer(s) have been proven correct, please accept one.

[user228546]

Thanks guys. This helped me figure out what was causing the "rotten egg smell" in my basement before I called the gas company emergency number. Hopefully the corrosive effects on nearby equipment will be minimal. :(

[Andy Joiner]

Thanks @bqDraco. Follow on question: I read that "Over-charging a lead acid battery can produce hydrogen sulfide". All 4 batteries were deformed by heat/gas when we opened the case. Could one faulty battery cause all 4 to bloat?

[bwDraco]

Either a cascading failure occurred when one battery failed, overloading the remaining batteries and causing them to fail in turn, or the UPS itself malfunctioned and drove excessive voltage into all the batteries. Another possibility is one battery overheating causing the other batteries to be exposed to high temperatures and hence failing in a chain reaction.

[Anthony X]

Perhaps a cleaning of any affected surfaces with a solution of baking soda and water to neutralize the acid? FWIW, for most people, the "rotten egg" smell of hydrogen sulfide will be repulsively strong at concentrations well below anything harmful. If it's just noticeable in the air, it probably won't hurt you.

[barbecue]

Actually, one of the dangers of hydrogen sulfide gas is that the unpleasant smell only applies at lower concentrations. At higher concentrations, the smell may actually seem sweet, and your sense of smell can be deadened very quickly, making you unaware of how much exposure you're having. link

[Xen2050]

@barbecue The symptom list from bwDraco's answer (and the osha pdf link mainly agrees) shows eye irritation and damage (may occur?) at lower concentrations than the sense of smell disappearing, but could take hours or days to show up for "lower concentrations. Do you know if your eyes would be burning and irritated immediately, even after it's "numbed" your sense of smell?

[barbecue]

@Xen2050 In many cases, eye and throat irritation occur very quickly, but that may not be sufficient warning to avoid injury. H2S is so toxic that even a couple of breaths can produce very serious injury, or even death.

[Neil]

Jesus, guys. You make me feel like I need to exit the office for a breath of fresh air.

[Joris]

This should be redundant, but.. store the battery outside until you can dispose of it! Also replace the entire UPS, chances are it's going to do this again to the other batteries or any replacements.