In this task, a passage will be given and the goal is to generate a question about temporal relations based on that passage. A temporal relation describes the relation between two things with respect to time e.g., something happens/starts/terminates/... immediately/shortly/usually/... before/after/during/... something else.
Your question should include an event, or ask about an event, and should not be a yes/no question.

Passage: A false fire alarm went off at a state-run nuclear fuel reprocessing plant northeast of Tokyo Saturday, nearly four weeks after it leaked radioactive substances following a fire and explosion. The alarm sounded at about noon at a facility for mixing nuclear waste with asphalt at the plant in Tokai Mura, about 115 kilometres (70 miles) from Tokyo, the Power Reactor and Nuclear Fuel Development Corp. (Donen) said.
What event has already finished?