We are rehabilitating an existing house and we replaced all the insulation with new fiberglass insulation. A worker spilled water on a section of the insulation and it is oily to the touch. Also, the floors have darkened, and underneath where a box sat on the floor, it was still light. What is happening?

All the insulation that got wet should be removed at the expense of the workers company. What exactly did he spill, it wasn't water if it feels oily. The floors, likely unrelated, can you wipe with a white towel and pick up anything?

More information. The "spill" was accidentally turning on the water pipes. The plumber checked them and it was just water. They are all new plumbing pipes. The insulation is not oily when dry, but it is when wet with water.
As to the floor, there is nothing that gets picked up with the towel. It has just turned a darker color. FYI: The insulation has been up for a week. The floors have been exposed for quite a while without changing color.
Should we get the air quality tested? It is very perplexing.

The mystery is solved!! First, one worker did mistakenly turn on the water. And when he checked the insulation, it was oily. A different worker, over the weekend, put his compressor in that room as he worked in another room. The compressor leaked and sprayed an oil throughout the room and into others. The job he was doing really didn't need a compressor, so we never knew it was in the house. The oil mist was so fine, and the floor wood was so old, it just soaked it up so it didn't wipe up. He never admitted it, so he's fired. The real lesson, you always have to be there to check the work. Thank you so much for your time.