1.   Spagnoli at first hesitated to make daguerreotypes because one of the main developing agents is deadly mercury vapor.

2.   When the mercury vapor settles on water, bacteria cause chemical changes in the mercury, turning it into the more-toxic methyl mercury.

3.   Ensuing tests determined a high level of mercury vapor escaped when the room was opened.

4.   The street lights of sodium vapor also has the red spectrum while the mercury vapor has the blue spectrum.

5.   Thor said in a statement it had never denied the three employees suffered mercury poisoning as a result of mercury vapor that entered their breathing apparatus.