Times Past

Explosion in San Luis Obispo caused power crisis for city in 1907

The San Luis Gas and Electric Company's gas house at Pismo Street just before Archer Street, as seen in 2010.
The San Luis Gas and Electric Company's gas house at Pismo Street just before Archer Street, as seen in 2010.


The Daily Telegram’s headline on the morning of Oct. 14, 1907 created a great deal of commotion locally.

Earlier this month, on April 9, the Public Utilities Commission approved a record $1.6 billion fine against Pacific Gas & Electric Co. for violating state and federal pipeline safety standards in the 2010 San Bruno explosion that killed eight people.

Reports of the PUC’s actions caused readers to ask me about local gas explosions. The 1907 story stated that the fire “. . . yesterday morning (at) the San Luis Gas and Electric Company’s plant . . . threw San Luis Obispo into darkness last night. The casualty originated in some unknown manner, but the theory is advanced that it was caused by the igniting of gas which had been generated from the crude oil used for fuel.”

In fact, the explosion was from the large retort used to heat asphalt-like oil-bearing shale to produce “manufactured gas.” Natural gas was not available here until the 10-inch in diameter pipeline was installed in 1927. About 2.8 miles of that line is being replaced as part of the Los Osos Valley Road overpass expansion.

The engineer, J. F. Parks, had been badly injured and was “taken to San Luis Sanitarium where Dr. W. M. Stover dressed his wounds, and while he is not suffering much pain, his burns are quite serious . . .”

The William Weeks’ designed San Luis Sanitarium at 1160 Marsh St. later became the first French Hospital. Now the beautifully restored architectural treasure is home to private offices. “A quick response was made by the fire laddies, but the fire was too far advance[d]....” to save the interior of the building. This was “accounted for by the tar paper used in the construction of the building.”

The 1907 event was a “double whammy” for the city. It lost both of its sources for street lighting. By 1902, the city was literally bristling with outdoor carbon arc lamps for illumination. These were identical to early search lights and motion picture projector illumination. A very bright light can be created by an electric arc through the air between two carbon rods. Such a lamp was placed atop the Andrews Bank Building.

In 1881 the downtown merchants of San Jose placed arc lights atop a 237-foot-tall tower that straddled a main intersection at First and Santa Clara. Other California cities followed, mounting arc lights on small towers atop buildings and on ordinary streetlight poles.

The San Luis Obispo Gas and Electric Company had to supply great quantities of electricity as well as manufactured gas for its more traditional customers.

Partial electrical service had been restored, but full street lighting would “not be resumed until the larger dynamo is restored.”

Citizens were warned to curb their use of electricity, “otherwise it will be impossible for the company to furnish the requisite amount of light, and the city may be in total darkness for some little time.”

On Oct. 19, 1907, the Daily Telegram reported that “the structure was almost a total loss and insurance will be fully paid.”

The Caen Fieldstone walls from the Los Berros Quarry were all that were saved and a corrugated metal roof replaced the tar paper.

Future mayor Louis Sinsheimer’s decision to build his gas house out of stone had saved it from total destruction.

Despite reportedly weak foundations, the gas house can be seen today along Pismo Street just before Archer. The most frequently asked question that I’ve received since beginning this column in 1984 is “what is that beautiful but empty stone structure?”

There was a lesson learned from the explosion at the gasworks:

Sinsheimer had the electrical generator removed from the building. Leaking methane gas and sparks from a dynamo made a wicked combination.