So there may have been arsenic in the old lace?

I guess lace isn't often coloured, but if it was....

This comes under the category of "things I feel I've read a bit about before, but it didn't stick much in my memory". 

At the Atlantic, there's an interview with the author of a new book which discusses the rather disastrous popularity of arsenic in the Victorian period - with it widely used in popular dyes for wallpapers and cloth of all kinds.  (And also, strangely, foods!)   An extract:

Factory workers were getting sick—and many died—because they were working with green arsenic dye. It was fashionable to wear these artificial green wreaths of plants and flowers in your hair that were dyed with arsenic. In wallpaper factories, workers were becoming really unwell, especially when they were working with flock papers, or papers with small fiber particles that stick to the surface. The workers would dye these tiny, tiny pieces of wool or cotton in green, and while doing so would inhale them and the particles would stick to their lungs. The manufacturing process created a lot of dust from the dye—the dust had arsenic in it—and this created major problems for the factory workers as the dust would stick to their eyes and skin. If there were abrasions on their skin, the arsenic could get directly into their blood stream and poison them that way as well....

Before legislation was passed, bakers used arsenic green as a popular food coloring. Sometimes, a baker was given flour or sugar with arsenic in it unknowingly, but other times it was used as a bulking agent. You wouldn’t believe the kinds of things that were put into Victorian foods as bulking agents. It wasn’t just arsenic, there were lots of weird things. Flour was expensive, so they would resort to adding other things.

There was an orphanage in Boston and all these small children were getting really, really sick and they didn’t know why. It turned out that the nurses were wearing blue uniforms dyed with arsenic and they were cradling the children, who in turn were inhaling the dye particles.

That’s another thing, too: Green was a color that was always seen as the culprit, simply because it was so desirable at the time, but many other colors used arsenic as well. When the National Archives did testing on the William Morris wallpapers, all of the colors used arsenic to some extent. These colors were exceptionally beautiful, and up until this point, it was not something they could achieve without the use of arsenic.