Last week we saw a HAZMAT incident where over 50 workers were transported to medical facilities after ferric sulfate and sodium hypochlorite (bleach) were mixed together. From recent press updates, what happened on Wednesday (2/27/19) sure does sound like a truck carrying one of these chemicals was unloaded into a tank of the other chemical. The details of how this happened have not been disclosed, but we were told this today:
The two chemicals – Ferric Sulfate and Sodium Hypochlorite are used to treat water but are meant to be kept separate. Deliveries of the chemicals from contractors occur at different parts of the plant. On Wednesday they were delivered to the same location. “It was an immediate reaction and that’s why we were immediately able to contain it. We knew right off the bat once this had happened we would need to seek medication for those who were in close proximity,” said Birmingham Water Works spokesman Rick Jackson. Interim General Manager Michael Johnson informed the Birmingham Water Works of the cause Thursday during a regularly scheduled board meeting. Utility officials were not able to explain why the chemicals were mistakenly delivered to the same location. Johnson told the board a new dual sign-off policy would be enforced at the plants to ensure the chemicals are properly delivered in the future.
This, of course, is NOT the first time these two chemicals have been accidentally mixed and it seems that injuries are sure to follow as the off-gas of this reaction is Chlorine gas. There is a sister to ferric sulfate… ferric chloride; and in 2001 the same type of accident occurred and sent all seven (7) workers to the hospital. Here is how OSHA says it all went down: