"The insurance no longer covers it."

Jokes aside, there almost was such a situation. I don't remember which drug it was and can't find the source now, but due to random contamination of factories by a particular form of crystal, the medicine stopped forming as it should. It first stopped in the US and when a team traveled to the European factory to figure out what they were doing differently (medicine still worked), they contaminated the European factory as well knocking out all production. They eventually figured it out and cleaned the contamination but it was a rather scary close-call.