The calls made to 911 from a Longview paper factory minutes after a chemical vat burst, killing at least eight people, have been made public by officials.

As they continued to respond to a huge chemical tank leak earlier this week, crews on Thursday retrieved six dead from a Longview paper factory. With the addition of two individuals who were pronounced dead at nearby hospitals, the confirmed death toll from the Tuesday tragedy now stands at eight.

In what Longview Fire Department Chief Brad Hannig described as "an active and hazardous environment," three additional persons are still missing and are thought to be dead. The deadliest industrial accident in Washington state in 96 years occurred when a highly caustic substance leaked into nearby rivers, killing and injuring workers. What we know about the catastrophe and the current recovery attempts is as follows.