Chapter 11 — The City Has No Smell

The night shift at the settling tank begins with checking for things that aren't on the electronic board. Van knew that so she didn't go straight to the control room. She walked through the row of lockers, looked at the masks hanging on the right hooks or stuffed into bags, asked who had just changed shifts, who had a headache, who drank coffee for dinner.

Tung led her into the processing area at 11 p.m. Dirty water is led through large tanks, the surface bubbles slightly under yellow lights. The smell here is very characteristic: mud, sulfur, detergent and a sour layer of organic residue. Tonight, there was no scent clear enough to show the way.

“Everything is so clean,” said a worker named Dat.

Van asked: "Is it clean or can't smell?"

Dat shrugged. "I only work here. Those two sentences have always been used the same way."

He wore a mask according to regulations, but when passing through the sub-pumping area, he took it off to talk because of the loud noise of the machine. Van immediately reminded her to put it back on. Dat apologized, saying it felt like stewing even though there was no smell.

Tung checked Dat's personal meter. Index within limits. The ventilation fan runs full circle. Van measured his breathing and found no serious abnormalities. She asked if she could write down the symptoms.

“If I write it down, the foreman will say I'm weak.”

"I wrote it down to know if there was any change in the shift, I didn't write it down to conclude that you were weak."

Dat looked at Tung. Tung said: "Just write it down. If anyone asks, tell me to request it."

They kept going. In the hallway between tanks two and three, a new worker named Hau stood wiping water on the floor. He didn't cover his nose, didn't cough, but his eyes were red. Van asked if he saw anything else.

“No. I just feel hot.”

“Do you know how this area used to smell?”

“I've only been here for ten days.”

Tung looked at Hau. “Have you learned about smell and gas signals?”

Hau said yes, but the training emphasized that the Clean Class had reduced odor. The instructor said that if there is no smell, check the watch, no need to panic.

Van recorded what he said, not blaming the instructor. A sentence that is correct under normal circumstances can be dangerous if used habitually under other circumstances.

Suddenly, a short hissing sound rang out from the south sump. Tung turned around and signaled everyone to stand still. No smell. Dat's personal meter is still green. Hau asked if it was a valve.

Tung took the lamp and went ahead, Van kept his distance. An auxiliary air pipe vibrates, the connection has condensate. Tung called the control room and asked to reduce the pressure for seven minutes. Quynh, who was on night duty, answered the phone and asked what process needed to be activated.

“Manual gas check in tank three. Do not increase Clean Layer dose.”

“Odor sensor is low.”

"I know. So no increase."

Quynh transferred the order. Huyen is at the data receiving center and hears it through the group channel. She asked Van what symptoms he had. Van replied that it was not enough to make a conclusion, but Dat and Hau both had red eyes, and one person in tank two just reported a headache.

They sampled the air at three altitudes. Samples close to the floor have higher humidity. The sample in the middle of the corridor had a peak of evaporation that was not recorded by the fixed sensor because the measurement period was too sparse. No one called the substance right away. Technicians take samples and send them to the analysis room.

“If we had smelled it, we would have stopped sooner?” Hau asked.

Tung replied: "Maybe. But maybe we got used to it and don't stop."

Van looked at him. “Don't make smell your sole gatekeeper.”

"I didn't turn. I said it was a signal."

Quynh arrived at the tank at 00:18. She did not wear the right size safety shoes and had to borrow them a pair from the spare closet. Seeing Hau, she asked what training he received when he felt unusual without smell.

Hau said: "Inform the shift leader, leave the area, check the machine."

“Have you done it yet?”

“I thought it was hot.”

Quynh does not blame. She asked to stop training based on the saying "no smell, it's okay", replaced with a specific sequence of actions: symptoms, sound, heat, pressure, teammates, gauges. Huyen recorded the order in the file at 00:27.

After the pressure stabilizes, the hissing noise disappears. Gas samples need further analysis. No one fainted, and there was no evacuation order. One might consider it incident-free. Van did not agree.

“Having an unusual episode is enough for many people to react,” she said. “We don't know the cause yet, but we know the odor-based warning procedure has been placed in an odor-free condition.”

Dat sat in the break room, drinking water. He said in the past when there was a problem with the tank, the smell was what made everyone look up at once. Now each person looks at a different type of machine. If their device is green, they are afraid to bother others.

Tung asked: "What kind of process do you want?"

"If one person reports symptoms, the person next to them must stop and check with them. There is no need to wait for that person's phone to turn red."

Van wrote down the proposal. It does not replace measurement, but it prevents one from being forced to demonstrate one's body in solitude.

Huyen sent the data sheet from the center. She points out that the vapor peak occurs precisely from the Clean Layer system reducing dose because of the low odor sensor. There is no evidence that the Clean Layer created the peak. It is possible that the system causes the odor signal to be masked for short periods of time.

Quynh asked: "How will you write?"

Huyen replied: "The temporal relationship between dose reduction, gas peak and symptoms was noted; the mechanism and specific substances have not been determined."

Quynh said: “That sentence will make people ask whether the whole thing should be stopped.”

“That's a question they have a right to ask.”

Late at night, the analysis room sent preliminary results: the sample showed signs of a low organic gas mixture, did not exceed the short-term toxicity threshold, but the data was not enough to rule out repeated exposure. Huyen read the results to everyone.

Hau asked: "If I don't exceed the threshold, can I go to work tomorrow?"

Van said: "The decision to go to work is not based on just one sample. You can be transferred, have your symptoms monitored, and not have to work in that area without completing the test."

Hau nodded, although he was not completely reassured.

Tung took him to the changing area and showed him how to record it in the shift book. They do not promise that all cases will be resolved immediately. They just create a record regardless of whether Hau smells it or not.

At dawn, the Clean Layer system begins its scheduled cycle. Quynh requested that the settling tank area not be sprayed until the sensor was rechecked and conditions were assessed. The smell of mud returned was very light. Dat said it strangely reassured him.

Van heard it and asked: "Do you want to keep this smell?"

“No. I want to know it's there, then know why it's there.”

Huyen wrote down that sentence. At the settling tank, there was not a single heroic moment. Only a group of people decided that the absence of odor was not enough to end the process safely. A new worker has the right to believe his symptoms. A technician does not increase the dose just because the sensor is green. A doctor keeps the unknown portion of the file intact.

The City Without Smell began to learn how to work with other signals.

The next morning, Dat asked Suggest reorganizing the walkway around the settling tank. He wanted each ward to have a sign recording abnormal sounds, pressure, heat and symptoms, not just a “no smell is normal” sign. Hau said new people need someone to accompany them for the first week, because personal meters do not help them understand the pumping sound.

Tung brought the proposal to the safety meeting. The foreman asked if it was necessary to do so much when the gas sample results were below the threshold. Van replied that the threshold is a value under measurement conditions, not an exemption for all times. She asked to record additional sampling time and data loss.

One worker said if they recorded too many, the shift would be slow. Dat replied: "A shift that is delayed for ten minutes is still faster than a shift that is stopped because you don't know who is having difficulty breathing."

The foreman did not agree immediately, but gave him a one-week trial. Tung set up a recorder at three points, Hau took on the task of checking the board each shift and was given time. The first time, a newbie doesn't know how to describe the vibrating sound. Hau did not fix it; He let him listen to the old recording, pointed out the differences and wrote that he needed a guide.

Van looks at the symptom diary after three days. The number of people reporting increased, but the number of people being sent out of the area early also increased, and the number of people having to quit their jobs decreased. The data sheet does not make the sump area look cleaner. It makes the process less dependent on an easily lost signal.

Huyen sent the summary to Quynh. Quynh asked if this model could be used at other stations. Huyen replied that it is possible, but it requires pay, training and time. A safety system should not take the voluntary kindness of workers as free parts.

Dat heard this and laughed: "Finally, someone recorded the guard's time."

Huyen edited the report again. A city without smell can still hear the pump, see red eyes, count breathing, measure pressure and ask if a new person understands the process. Other signals do not render the nose useless. They have to do it alone.