With the second major underground fire in four years roaring last Friday -- spectacularly so, we might add -- Mayor Gavin Newsom wants some answers from PG&E. If you recall, in August 2005, an underground PG&E vault blaze occurred in the Financial District, critically injuring a passerby. That fire, according to CBS 5, "was caused by high levels of moisture in the oil inside the high-voltage chambers on the transformer." A follow-up investigation reveals that five additional transformers within in San Francisco "had high moisture levels" as well. Anyway, Newsom claims to be unhinged by last week's manhole blaze, saying. "I've been at this a lot as mayor of San Francisco, some more problematic events, not just this event. We'll work through them." PG&E promises a thorough investigation. Polk Street at O'Farrell remains closed for investigation.