Mercury is a dense, heavy, toxic material. Mercury can be found in some household thermometers and dental fillings. Mercury has a high surface tension and tends to pool easily. When disturbed, the material can separate into extremely tiny beads that scatter and can become trapped in cracks or pores in floor material. These tiny, trapped beads can be missed by the vacuum and remain in the facility in minute quantities.
Mercury evaporates easily and can become a breathable vapor, which can cause health problems.
However, not all spilled mercury becomes vapor since the beads eventually develop a chemical coating or get covered with dust, greatly reducing the rate at which they vaporize. Workers cleaning up experimental areas at the Lujan Center wear protective clothing and respirators as a standard precaution. Multiple types of samplers are used to detect and measure mercury vapors. Workers also wear special filters on their respirators that change color to indicate prolonged exposure to the material. Workers have not observed any filter color changes at the Lujan Center.