A neighbor took video on Oct. 17 and alerted the city.
Officials say 916 gallons of a nonhazardous solution came from a Tesla research facility on Oct. 24.
The spill was seemingly an accident.
On Friday evening, Palo Alto's city manager and the fire chief hosted a community meeting.
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"When we first walked over to ask the cleanup crew what was spilled, they said that it was just water that had dye in it and the cleanup was just there for the 'warm and fuzzies.' Then it came out it was coolant that was spilled a few days later, and then it came out it was sodium hydroxide," one resident said during the Q& A.
A point residents wanted to address is why it took the city five days to notify them of the spill and cleanup.
"The same thing happened with the VA spill, same thing happened with the CPI incident, you know, is how quickly these things should be communicated to us as neighbors. Whether they're serious or not serious, let us make that determination if we're concerned or not," Palo Alto resident John King said.
Officials say a formal investigation as to what exactly is in the solution, and how far it reached upstream will take time.
Tesla did the initial field PH testing.
RELATED: Tesla chemical spill: Palo Alto apologizes for delay in notifying residents
"The initial test is with a PH test to test the acidity of the material. I always say we don't necessarily always know what it is, but we also know what it isn't," Fire Chief Geo Blackshire said.
The city said as far as next steps, they will change their notification protocol.
"Basically, any significant incident going forward, we're going to step up our communication," City Manager Ed Shikada said.
Residents appreciated the city holding this meeting.
Winter Dellenbach said the amount of neighbors that came out on a Friday night is an indication they deeply care.
"You cant just care and not get involved - if all you do is sit around and care, it doesn't meant anything. You have to do something," Dellenbach said.
Early next week, the fire department will conduct testing on Matadero Creek to make sure it's clean and there are no remnants from the spill.