When you’re out and about, traveling or visiting new places or events in and around your hometown, you have more than likely used or at least have seen a portable toilet. And more than likely, you have probably stepped inside and looked down to see blue “stuff” at the bottom of the toilet. “What in the world?” you might ask yourself, as you continue with your business, before leaving the space never to think of this odd blue liquid again.. until you step back into the next porta potty.


The easy answer is that it’s a chemical we use in the business to hide the smell — and the sight — of well. your business. This chemical deodorizes, prevents the growth of odor-producing bacteria, hides unwelcome sights, and masks any unwelcome smells. The actual ingredients are dye, biocides, detergents, and fragrance. The biocides are what keep the bacteria from growing and producing the odor we are all happy to live without while the detergents help keep fragrances uniform, or overall similar, so you don’t smell too much of one thing over another, while the actual fragrance that gets added helps to mask anything else you might otherwise smell. Finally, the dye in the liquid helps turn everything that blue that you see when you step into the toilet (we’re not suggesting that you actually look down there, though). This helps with a few things: You won’t be able to see the things that you don’t really want to see while also helping people like us know when the chemicals aren’t working anymore.


So sometimes, you might notice that the “blue stuff” has turned green. Nothing to be alarmed about, but it does let us and you know that the blue stuff isn’t doing its job anymore. See, the blue dye will turn green when it’s mixed with other colours like the yellow “stuff” people leave in there. When enough of that “business” is left in the portable toileet, the chemical gets “used up”, and the green colour lets everyone know that it’s time to pump the potty, clean up, and refresh with fresh chemicals. This doesn’t happen often, as porta potties get used frequently enough that they also get cleaned out frequently.

However, you probably shouldn’t be looking down in the belly of the proverbial beast. That’s up to the professionals. (That’s why you’re paying us).


All of this may seem pretty uninteresting, but you’ll be happy we use the blue stuff once you learn about how people used to deal with porta potties.


Once upon a time, when people used outhouses, which are the now long old cousin of the present-day portable toilet, they would sprinkle a little lye over what they left in there. Since outhouses were permanent, they were dug into the ground, meaning everything was left in a giant hole underground. The lye was meant to cover up the smell, but when mixed with Urea, a chemical in urine, it creates ammonia, (available in many cleaning ingredients because of its effectiveness in cleaning) which is a very strong smell on its own. This smell is bad on the lungs, but flies don’t like it, and neither do those odour-producing bacteria we talked about earlier.

When doing its job at preventing odour, it has a very special reaction when it comes into contact with poo. Pooh requires a certain pH in order to decompose. Lye raises the pH which slows down decomposition (which also puts off odour). This reaction forms a sort of dry “crust” which helps keep down the odour.

But because of the chemical, it can burn skin, and like we mentioned, harm the lungs, so people had to be extremely careful not to spill it on the seat of the outhouse, or on themselves when they used it. This is one reason it is not a very popular chemical anymore.


Formaldehyde is another chemical people would use in order to try and keep the smells and flies away from the outhouse. It’s commonly used as an embalming liquid in funeral homes. It’s good for killing most bacteria and fungi. It destroys viruses and slows down decomposition like Lye. Unfortunately, it’s been proven to interfere with sewage breakdown processes in sewage plants, which is one of the reasons it’s not used anymore.


Now, we use more biologically friendly enzymes in order to help with all of the previously mentioned odours and processes. The reasons are many; It’s not bad on our health, and it makes handling the actual “stuff” more manageable because without the chemicals, what is left inside the porta potty is classified as sewage, as it once was labeled. The chemicals are still dyed blue, (because when you think about it, it’s the least offensive color that still does the job) but they aren’t going to harm you if you come into contact with it or smell it.

So there is your answer to the blue stuff in portable toilets. It’s basically everything you probably thought it might be, but there might be a little more to it than you might have been thinking, too. We hope this journey through the history of the outhouse and back was a good read for you. The more you know!

When you’re ready to hire a Portable Toilet, give us a call!

Midland Toilet Hire – 0800 999 2820

Portable toilet services

Portable toilet services

1st floor, Shah Residency near Lal masjid Baraf wala, Firdous Colony, Nazimabad, Karachi