SAN FRANCISCO (BCN) – An arsonist burned several portable toilets in San Francisco over the weekend in what seems to have become an annual ritual in the city.

An arrest was made after Saturday’s fires, which occurred at about 7 p.m. at a construction site in the 400 block of Mission Bay Boulevard South, near the UCSF Mission Bay campus, according to police.

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Michael Warner, the 27-year-old homeless man arrested is not believed to be the culprit in a series of similar arsons in recent years.

Police said seven toilets and three hand-washing stations were destroyed.

A witness to the fires saw a man climbing out of the construction site over a fence, according to police. Officers detained the man, and the witness confirmed he was the same person.

According to police, seven toilets and three hand-washing stations at the site in the 400 block of Mission Bay Boulevard South were destroyed. An eighth toilet was damaged.

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Esparza and fire department spokeswoman Lt. Mindy Talmadge said today that Warner is not believed responsible for a string of portable toilet arsons throughout the city between late 2008 and last year.

“Based on the circumstances of the incident, it does not appear to be related to the previous arsons,” Talmadge said.

Warner has no fixed address and told police he was not from San Francisco, according to Esparza.

In the fall and winter of 2008-09, 27 portable toilets were burned throughout the city; in December 2009, several more went up in flames.

No injuries were reported in any of the fires, but the fire department warned that the blazes were more than just a nuisance because they had the potential to spread to nearby trees and homes. The lavatories also cost about $2,500 apiece.

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