Chlorine vs My Nasal Cavity ~ Can’t Go Home Until Cleaning Is Done! ~

Hello everyone! I’m Shohei.
This column is written mainly based on my field experience.
After being on site for over 10 years, there are truly many things that happen. I’m writing about things I remember, as they come to mind.
Well, please read it casually, like “Oh, so that’s how other factories are.”

TOC

“Do You Like the Smell of Swimming Pools?”

“Do you like the smell of swimming pools?”
Suddenly, but if you’re of a certain age, doesn’t this question bring back nostalgic memories? Summer days of childhood, tiptoeing on the hot poolside with excitement thinking, “I want to jump in soon!”
I actually used to like that pool smell (or more accurately, the smell of chlorine).
…That was until a certain incident turned that emotion into “severe PTSD.”

A Chance for Deep Cleaning!

This is a story from when I worked at a small experimental plant factory.
In this experimental facility, we were constantly growing various vegetables, and it was rare for all crops to reach their harvesting period simultaneously. It was in a perpetual state of “fully occupied.”
But finally, a miraculous day came when all vegetables were harvested!
“This is our chance for a deep cleaning!”
Even though it was experimental, it’s still an environment for growing living things. We needed to thoroughly remove accumulated dirt and bacteria.
When I peered into the nutrient solution tank…
“Whoa…”
It was dirtier than I had imagined. Tiny fragments of roots that had flowed in during the circulation of the nutrient solution, along with algae-like substances, had accumulated.
“We need to be thorough!”

Enter Sodium Hypochlorite

The final stage of cleaning: sterilization and disinfection.
Here enters “sodium hypochlorite,” a member of the chlorine-based bleach family. It’s the source of that distinctive smell used in pool disinfection.
Ideally, this should be used after completely draining the nutrient solution from the tank. However, this equipment had a design flaw: it was difficult to drain completely, leaving about 10% of the nutrient solution behind.
“Even after draining, quite a bit of nutrient solution remains…”
I should have repeated the process of filling with water and draining several times. But there was time pressure with another experiment scheduled for the next day.
“Well, it can’t be helped…”
This “it can’t be helped” was the fork in the road of fate.

Ticket to Hell

I added the sodium hypochlorite and turned on the circulation pump. With a “whoosh” sound, the liquid began circulating through the equipment.
At first, everything was fine. I was even sniffing nostalgically, thinking, “The pool smell brings back memories~” as I continued cleaning.
But after about 10 minutes…
“Hm? Are my eyes stinging?”
And 5 minutes later…
“Huh? My nose is running…”
And then suddenly,
“Ugh… AAAHHH!”
Unstoppable tears began flowing from my eyes, and a waterfall of mucus erupted from my nose!

Forced Labor Through Tears

What was happening was actually a very simple chemical reaction:
Remaining nutrient solution (acidic) + Sodium hypochlorite (alkaline) = Chlorine gas production
I should have remembered this from middle school science class, but I had completely forgotten.
In normal amounts, it wouldn’t be a problem, but either the acidity of the nutrient solution was too strong, or I added too much sodium hypochlorite… A textbook chlorine gas experiment was unfolding inside the plant factory.
“I can’t take this anymore… let’s stop…”
But the next experiment was scheduled to start the following day. I couldn’t abandon the cleaning midway.
I opened the doors wide, but still had to work through the remaining chlorine gas, as if working through tear gas.
“This is like trench warfare in World War I…”
My eyes were bloodshot, my mask was soaked with tears and mucus, and my nasal passages stung with every breath.

The Tragedy of Chronic Sinusitis

What made the situation even worse was that I suffered from chronic sinusitis.
What happens when chlorine gas enters the complex and convoluted nasal passages of a sinusitis patient…
Someone might say “that’s a medically interesting experiment,” but for the person experiencing it, it’s nothing short of hell.
After this incident, my nose completely shut down for about two weeks. When I woke up in the morning, my mouth was so dry it felt like I had been licking a desert.

Lesson: Chemistry is Honest

In the end, the cleaning was completed, and the next day’s experiment began as scheduled. But my nasal passages were the only casualties.
What I learned from this experience is clear:

Never add sodium hypochlorite directly to nutrient solution
Always completely drain the nutrient solution before disinfecting
“Well, it can’t be helped” is a danger signal
Chemical reactions produce honest results regardless of feelings

Especially the third point. When the phrase “well, it can’t be helped” crosses your mind, it should be taken as an alarm that “you absolutely should not do this.”

Since Then…

Even now, when I pass by a swimming pool, I unconsciously try to walk away quickly. The chlorine smell that I once “liked” has now transformed into “the scent of trauma.”
For all of you working in plant factories, cleaning is important, but please don’t disregard the laws of chemistry. For the sake of your nasal health…

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