None of this means you should get your panties in a wad because there is
a mercury wetted relay in the house.

In the mid 80s I was involved in the start up of a 100KW photovoltaic
demonstration project. I worked for an electric utility, and they wanted to
show how great amorphous silicon solar cells were, so they could manufacture
and sell them.
The PV array was capable of 300VDC at around 350 amps at high noon on the 4th
of July in the deep south. The array fed 4 25KW inverters which converted all
that DC into 480 VAC 60HZ which was put on the power grid.
The interrupters, or circuit breakers to the inverters were Mercury wetted
contactors. The guy that designed the inverters used the AC interrupting
rating of the contactors. The PV array was capable of more than double the DC
interrupting rating of the contactors resulting in 4 exploded Mercury wetted
contactors. The inverters had problems which resulted in full load rejection
during start up.
Well, the exploded contactors produced an abundance of mercury vapor as well
as little blobs of the stuff all over the floor in the inverter building. This
just about closed down the whole 1.4 million project, because a lot of folks
got their panties in a wad. As for me, I went around sucking it up with a
suction tube, putting it in a bottle for future use in antenna projects.
73 Gary N4AST