Very hard to find updates on this story! From KFVS12 4 hrs ago:

"A leak Sunday night at the Honeywell plant in Metropolis is currently under investigation, according to Peter Dalpe who works with the company.

Dalpe says the leak, which happened around 7:30 p.m., was due to an equipment failure in the main production building.

There were no injuries reported and there is no indication that any UF6 material left the site, according to Dalpe."

less than 50%
[link to www.kfvs12.com]