Largest accidental oil spill

The largest oil spill in history was the Lakeview Gusher, an oil well blowout in the San Joaquin Valley, California. Between 14 March 1910 and 9 September 1911, this out-of-control oil well released 9.4 million barrels (1,372,000 tonnes) of crude oil, of which less than half was recovered.

Lakeview No.1 was a seemingly unpromising well in the Midway-Sunset oil field, located around 45 km (27 mi) southwest of Bakersfield. It had been started by a local businessman, Julius Fried, in 1909, but had initially turned up nothing but dust. Fried cut his losses later that year, transferring the well and surrounding land to the Union Oil Company. They assigned the well to "Dry Hole" Charlie Woods, a skilled but notably unlucky driller, instructing him to extend it whenever he had a bit of spare time.

On the morning of 14 March 1910, Dry Hole Charlie and his colleagues were trying to free a stuck drill bit at a depth of 2,225 ft (678 m) when the ground started to shake. The stuck drill bit then exploded out of the well, smashing apart the upper section of the derrick. They had struck an underground reservoir of oil that was under extremely high pressure, creating a massive geyser (a "gusher" in the terminology of the time) that reached a height of around 480 ft (146 m).

The initial flow rate of the Lakeview Gusher has been estimated at around 125,000 barrels a day – that's around 12.66 tonnes a minute. Dry Hole Charlie commented that Lakeview, "must have cut an artery of the earth's great central storehouse of oil, whereas all previous wells had been merely pinpricks in the earth's thick hide." Tourists from all over Southern California came to marvel at this spectacular sight – which was seen as a symbol of the region's booming economy, rather than an ecological calamity.

Containing the oil was a major challenge. Usually oil-well blowouts died down after a few hours or days, but the Lakeview Gusher seemingly stabilised at a flow rate of around 90,000 barrels a day. It flowed in streams across the surrounding landscape, pooling in great ponds and lakes of oil. Enormous earth-and-sandbag dykes were constructed to hold back the torrent, and to prevent it from flowing into Lake Buena Vista, which was used by local farmers for irrigation. New pipelines were also built to transfer the oil to ports and refineries on the coast.

The gusher caused major financial problems for the Union Oil Company. The construction of the dykes and pipelines cost the company $350,000 (around $10 million in 2021 dollars) and the uncontrolled output of the well depressed the price of California crude from 60 to 30 cents a barrel.

About a month after the initial blowout, a wooden box about the size of house and made from 14 x 14 inch (35 x 35 cm) timbers was moved over the well in an attempt to control the flow. This was soon smashed apart. Eventually, in October 1910, workers succeeded in building an enormous circular dam around the well, and the weight of the oil contained in this pond reduced it from a towering gusher to a bubbling spring. The oil finally stopped flowing on 10 September 1911, when the pressure in the underground reservoir dropped below a critical threshold and the well head collapsed, sealing itself shut.

Of the 1,372,000 tonnes of oil released by the Lakeview Gusher in its 545 days of existence, less than half was recovered to be refined. By way of comparison, the Deepwater Horizon disaster resulted in the spillage of around 5,000,000 barrels (729,750 tonnes). The uncollected oil soaked into the soil or was carried away on the wind. Thick layers of oil-soaked sand can still be seen in the desert to the south of Maricopa, California, and the monumental sandbag dyke that was built around the well is still visible. As the oil was largely contained in one area, however, and prevented from catching fire, the ecological damage was minor compared to a marine spill like the Deepwater Horizon.