In the spring of 2008, the author took a new job as the Manager of Environmental Health and Safety for a construction engineering company, which had contracted with a large overseas fabrication company to convert a computer fab into a solar panel manufacturing facility. He took the job when the safety administrator suffered some health problems, and would be gone for a period (approximately two months). He subsequently returned, and all discussion in this paper was developed jointly with him and the EHS representative of the parent, XXXX company.

During the first week on the job, he became aware of an area of the building known as Level Zero, or the subfab area. The building had originally been built by a Japanese manufacturing company to build computer chips, but just before it was completed, the company announced that they would not occupy it, and were abandoning the project. The company had built this building to the exact specifications as an identical building in Japan, the story goes, and that "copy exact" requirement meant that they built the subfab exactly is it was built in Japan. But in Japan, apparently, they had water table restrictions concerning how deep they could build the subfloor, and so from the top of the main floor to the subfloor was about 7 feet. But all of the structure to support the floor was below this height, and therefore the real height of the Level Zero area for walking purposes varied from about four and a half feet to five feet. When the original floor was made, it was made of removable tile with holes in it for air flow. But to convert the flooring for use as a different manufacturing plant, with much heavier machinery, the flooring was deemed inadequate, and was replaced with a four-inch thick concrete and steel floor, reinforced with rebar.

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