To be honest about these ghost stories, they're nonsense. Compared to the anomalies I found over the course of my life, they hardly have any meaning. However, people are still afraid of them.
At the place I worked, there were a lot of deaths in the past. In every single room, floor and department, it was a daily routine before I took on my job as the director. The underground was Famous, Tomson and I were stationed was a place for detained Class-D personnel, one where they were cruelly tested before the rules changed and further developed into what they are nowadays.
The ghost stories in Site-29 are not limited to the underground. I could say that they existed in every place. It depends on your luck finding them.

Workers' Ghosts at the East Parking Lot
When the facility was newly built, workers who died while on the job would be buried here. After the burial, there was a funeral ceremony for them. Now there's a small shrine in the parking lot in memoriam. This eastern lot was the place where people frequently found the ghosts, but still a lot of people parked there due to the limited amount of space. The ones who found these ghosts often described them as laborers with hanging heads and their feet planted on the ceiling, or just as the noise of huge machines in operation. When parking here, you never had to worry that your valuables would go missing.

Dr. Lieat
Dr. Lieat was a very hard worker. She dedicated her whole life to her research. I never saw her go home, take a shower or eat anything. Also, she was very moody. One day, someone found her in the office of the 2nd-floor front corridor, where she had hung herself (nowadays, that room doesn't exist anymore). From that on, the night-shift personnel often saw Dr. Lieat walking down the corridor. Later in the night, 'Lieat' is often reported as walking backward and turning to face passers-by.

The Spirit House at the Middle of the Site
Every room in the Site is meant to be used. There is no such thing as an empty room, except for one. I know where it is but I will not tell, because there would be those senseless enough to attempt to find a way in. The characteristics of the room were the same as those of a small office. There was nothing, except the spirit house. It was the room for religious1 ceremonial purposes. These ceremonies were performed when there were things that were too haunted2 to be tolerated. You could even call them the major local spirits. The door was closed with wood, which was painted in the same color as the wall, making it difficult to be noticed. However, if you wanted to know where it is, you had to ask the lady in Thai traditional dress working in the Chemistry department. If you weren't familiar with it, you would never find it.

The Ghost Bridge
To reach Site-29, employees must cross a 50-meter long bridge. Under the bridge is the place where the homes of the Foundation personnel were located in the past. The bridge was bombarded at some point during the Second World War. All who lived there at that time died; most of them were families of the personnel. If you were lucky, you would see a group of people who walked on the air beside the bridge. Sometimes, you would see them walking under it where the canal was created.

The Prisoner Ghosts
I told you at the beginning that the underground was the place where the prisoners were detained and died, and even though there was a renovation, there are still people who saw the spirits. In the past, it was very haunted, so you could not say what was real and what wasn't; more recently, you can hardly find them. The personnel often hear these things now report things like creaking in the walls, dragging chains, shouting in the corridors at night. There was also this one agent who supposedly saw the 'ghosts' with their own eyes.
Remember Agent Philosafix? He used to work at this Site in the past. He also found one of the ghosts; it had chains around the ankles and knees, and it was- according to him- stepping into the elevator. Yes, the one that you, me, and everyone else here always uses.
…I didn't know that was the reason behind his transfer request.

A-37 Conference Room
A-37- the conference room completely decked out with classic looking wood paneling. There aren't any windows to allow people to see in. At least the air conditioners were cool. The sofas were comfortable, too. It was also located in an area where there was little foot traffic. The lazy personnel always slacked off in there, and I heard they found a ghost too. They were pulled, or dragged, to a body. I didn't go in there very often, but I heard from someone that it was headless.

This is the final story.
Nicolas Zheniche Sawellton
If you went to the canteen at the back of the Site and walked the circular way through 4 separate corridors, there was a black-and-white photo of a foreigner among of other photos. The nameplate read 'Nicolas Zheniche Sawellton'. He was one of the people from the main branch. He built up the SCP Foundation in Thailand. He and others like him hired Thai workers with the promise of high wages for managing SCP objects. Nicolas sent SCP-014-TH to the Foundation main branch from Thailand as a sign of co-operation. In 2003, Nicolas fell deathly sick all of a sudden and died just a few days later. His body was burnt and his ashes were scattered. After that, there were people who saw Nicolas in the Site- his spirit never went away.
Nowadays, there are still people who claim to have seen him, but only a few people actually knew him. There are a lot of foreigners at the Site now. Some say that if you find a foreigner you aren't familiar with, take a look at Nicolas' photo- perhaps you may have found him.

Footnotes
1. Buddhist or Hindu belief
2. by spirits/ghosts only