Humidity at PG&E Substation Likely Cause of Massive December San Francisco Blackout
- Posted on May 9, 2026
- By NPR
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- 1 min read
Humidity at PG&E Substation Likely Cause of Massive December San Francisco Blackout
A new report found the South of Market substation was susceptible to rain and had a “compromised” ventilation system, which caused damage to key infrastructure.
