An efficient solution to a historic drought, or an environmentally risky pact with the devil?
That's the question being raised by critics approximately Californian farmers who irrigate their crops with waste water supplied by oil companies, in an arrangement slammed as dangerous by environmental campaigners.
Driving into the parched region around Bakersfield, in the western US state's fertile Central Valley, it is evident how closely the agriculture & oil industries are related.
Lines of orchards stand near fields of oil wells stretched out as far as the eye can see.
Eighty percent of the state's oil production & 45 percent of the farming industry is concentrated in a single county, Kern County, said Madeline Stano of the Center on Race, Poverty & the Environment.
With temperatures frequently exceeding 40 Celsius (104 Fahrenheit) in the summer, water is in scarce supply.
After four years of record drought, farmers can no longer pump water from rivers whose levels are dangerously low.
Drawing from the water table is moreover increasingly difficult: more than 1,000 wells have dried up in the region.
In a bid to diversify supplies, the Cawelo Water District, a cooperative financed by local farmers, has for 20 years used waste water from oil companies.
Abby Auffant, spokeswoman for oil giant Chevron, explained that crude comes out of the ground mixed with water, from which it must be separated.
Separating the water from the crude is a process that actually benefits oil firms, according to Stano.
"It's complex for the oil industry to obtain rid of, so it's a win-win for the oil companies" when they are able to sell the water, she said.
Chevron's Kern River operation sells some 500,000 barrels of waste water per day to the Cawelo Water District, which currently gets 50 percent of its supplies from the oil company.
The water is cleaned by a filtering system & piped to a reservoir where it is combined with supplies from other neighboring oil plants, before being mixed with fresh water & then distributed to some 90 local farms & vineyards.
– A legal practice –
The farmers pay approximately $33 per acre-foot (1,233 cubic meters), compared to up to $1,500 for the same quantity of fresh water, said David Ansolabehere, head of the water distribution cooperative.
The practice is entirely legal: Chevron & rivals including Occidental Petroleum Corporation have a permit to sell the water. They have it tested by a third-party firm & then supply the results to California authorities.
"We're in compliance with all the testing requirements," said Auffant.
"There's a petrochemical content in our… permit & we have always met & been under it."
But environmental campaigners don't see it the same way.
"It's an experiment that the state of California & the oil industry performs without consumer consent," Stano said.
"In Chevron's own report we found benzine & acetone, which are carcinogenics" in the water sold to farmers, she said, claiming that the tests moreover fail to detect other dangerous chemicals.
"There has been a gentleman's agreement to promote deregulation," she added.
Santo denounced a "lack of state enforcement & oversight (and) blind faith in the industries for a long time."
Scott Smith of the Water Defense lobby group, founded by actor Mark Ruffalo, moreover criticized the testing methods, which he called "outdated."
"Chevron should be interested in partnering with more than just their complicit customer (Cawelo Water District) to protect health, community, environment & water resources," he said.
Almonds, grapes & other agricultural produce are not evaluated apart from their pesticide content, Ansolabehere admitted.
He noted that Californian authorities have decided to form a working group that could order tests on farm produce, after a Chevron report showed salinity which Ansolabehere admitted "was a bit high."
The group would moreover verify that chemicals like acetone or benzine "cannot obtain into the roots, the leaves & the fruit," he added.
Tom Frantz, a former & environmental activist, said the stakes are high.
"People would stop buying anything from Kern County for a while if someone received sick," he said.