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Comment by insaneirish | Hacker News Reader

From the article: "The chemicals in bleach “are persistent in the environment, and they’re also very corrosive,” she added."

This seems incomplete at best and disingenuous at worst.

It's my understanding that chlorine bleach breaks down into oxygen, NaCl, and water.

So, sure, you can argue that salt water is persistent in our environment and also corrosive, but that statement strikes me the same way as how people have long warned about the dangers of ever present dihydrogen monoxide in almost everything we consume these days.

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This jumped out at me too. If it’s very reactive (and it is) then it can’t possibly be that long-lived.

Yes, it's a very silly statement. That said, the chlorine that you breathe in when the bleach that you cleaned your bathtub with evaporates can't be good for you. Worse if you spray the stuff (and how we all made fun of Trump and his nebulized hydrogen peroxide).

Yeah. A lot of household chemicals or the reaction products are dangerous to inhale, but not many people seem to care to open the windows for ventilation.

When bleach evaporates, does chlorine come off? Or just water?

Chlorine absolutely gets in the air, can’t you smell it?

Bleach should be applied with ventilation in mind.

I thought that smell was chloramines, rather than chlorine itself?

I was responding to someone who appeared to be asking if any chlorine made it in to the air regardless of in which compound.

That is not what I asked.

I smell something, sure. But I don’t believe it’s chlorine gas.

It seems NaOCl is capable of forming various products when reacting with other chemicals common to the home environment: https://pubs.acs.org/doi/10.1021/acs.estlett.0c00573

Whether such products rise to a level of concern is another story.

Doesn't most bleach contain stabilizers? Perhaps that part of it. The other possibility is that when bleach reacts with stuff it can form other, more stable compounds.

Either way, I generally agree with your position. Bleach tends to break down pretty quickly compared to many other things.

> Doesn't most bleach contain stabilizers?

Not sure.

SDS for Clorox Regular Bleach: https://www.thecloroxcompany.com/wp-content/uploads/cloroxre...

It lists a single ingredient: sodium hypochlorite.

Ah, I might have been thinking about pool chlorine and some outdoor cleaners.

Pool chlorine is just slightly more concentrated bleach.

You might be thinking of certain types of pool chlorine tablets that include cyanuric acid. Really a terrible way to treat a pool, honestly, it builds up CYA in the water and eventually you can't get enough active chlorine to safely disinfect. And the only realistic way to reduce CYA is drain the pool partly or completely and refill. Properly maintained pool water only needs basic chemicals, and pure sodium hypochlorite (unless you're going to use a chlorine generator, in which case you'll end up buying a few hundred pounds of salt when you fill the pool).

Guess the SDS only covers components that require special handling? They have a page that mentions stabilizers: https://www.clorox.com/learn/what-is-bleach-what-are-active-...

If something in the mixture is potentially hazardous then it goes to mean it should be listed in the SDS?

Cyanuric acid is the stabilizer used in pool chlorine, but even it breaks down relatively quickly in the environment. https://pubmed.ncbi.nlm.nih.gov/4451360/

Also if chlorine is stabilized by cyanuric acid, it is no longer active in the environment - basically the cyanuric acid locks up the chlorine in an equilibrium so that it slow releases, which is why it's widely used in outdoor pools. Otherwise UV exposure would cause the chlorine to offgas rapidly and you'd need to add chlorine every hour or so during the day, which is obviously effort and cost prohibitive.

and it breaks down on it's own, pretty quickly, especially when hit by sun UV rays, which is why you have to chlorinate your pool so often. It also gets diluted easily by water.

Which is why you get a salt-water pool. So much better!

A saltwater pool IS a chlorine pool. The difference is that instead of adding sodium hypochlorite from a jug, you add salt to the water and use electrolysis (chlorine generator) to create chlorine gas and hydrogen.

Properly maintained pool water will have the same chlorine level either way. The "chlorine pool" water won't have quite as much dissolved salt, but over time it does build up.

Chlorine, yes, byproducts, no. And this massively cuts down on irritation & smell.

> irritation & smell

This is not a chlorine problem, this is improperly balanced pool water. Either way too much CYA, requiring a high concentration of chlorine to compensate, or high pH. The latter is the most common reason for irritating water.

You want to fix that in any case. Using a chlorine generator is no panacea, if you have high CYA you'll need high chlorine or it won't disinfect. And if you have high pH, you're not doing good things to your pool equipment.

Definitely worth buying a decent test kit and staying on top of things. It's totally possible to have crystal clear silky smooth odorless pool water, whether you use a chlorine generator or bleach. TFP is a really good resource to learn more, I strongly recommend any homeowner with a pool go there and do some learning.

Unless you have a way to drip feed chlorine into your pool it absolutely will not have the same chlorine level, unless you are running your sag incorrectly.

Automatic chlorine dispensers are fairly inexpensive (and certainly cheaper than a chlorine generator). There's very little reason to manually add chlorine yourself unless you're SLAMing the pool (shock level and maintain, if you're unfamiliar with TFP).

This is why you add cyanuric acid to the pool when you're setting it up. The sun can destroy an entire pool's chlorine in a few hours, but CYA will help slow that process down significantly, so that you can keep up with a chlorine generator or chlorine dispenser.

Afaik, cya also lowers chlorine ability to disinfect. So it is balancing act. And since cya does not break down, one have to be careful to not overdo tablets and such. I switched to liquid chlorine for that reason

and then liquid chlorine is impossible to find and doubled in price, so I ended up with salt water.

30% muriatic acid? They stock it in gallons around here.

Liquid chlorine is another name for sodium hypochlorite, aka bleach. We tend to refer to it as liquid chlorine when buying it for pools and it is usually stronger than anything you'd buy in the household aisle of the supermarket.

Muriatic acid (aka hydrochloric acid) is a totally different chemical. That will reduce pH in the pool, it is not used as a disinfectant. I personally recommend getting something weaker than 31.45% however, if you're not etching concrete.

In the 90s in Sweden (possibly other countries as well) there was a campaign to get people to stop using bleach (i.e. sodium hypochlorite). However, I have not been able to find any sources that could prove that use of bleach in the home would contribute to any environmental damage.

A campaign from who? Im also a swede so I grew up with the "DRINK MILK OR UR GONNA DIE!!" campaigns from the "neutral" milk lobby.

Is that on the ground floor of the neutral milk hotel?

no, it's in the aeroplane over the sea

I’m afraid I don’t have any sources at hand, but I believe Naturskyddsföreningen were involved (The Swedish Society for Nature Conservation).

aah yes I may remmber... I think they pushed for using såpa instead :D

They sure did! Såpa isn’t bad, but it’s not as effective as bleach.

neutral milk does not sounds like a tasty beverage.

I thought I remembered reading something that some amount can be converted into chloramines and that those don't break down quickly.

Chloramines are used to disinfect residential water supplies. I believe if you mix chlorine and ammonia, you get cyanogen chloride, which is toxic.

You would need nuclear chlorine :). Neither chlorine, water, nor ammonia contain carbon, so they can’t react to form anything containing carbon.

Chlorine reacts with ammonia to form monochloramine, which is fairly innocuous. Monochloramine reacts with more chlorine to form dichloramine and nitrogen trichloride, which are stinky and potentially dangerous.

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