> ## Content Index > Fetch the complete content index at: https://core-sector.ghost.io/llms.txt > Use this file to discover other available public pages before exploring further. # A California canyon took industrial acid because the rock looked solid. - URL: https://core-sector.ghost.io/a-california-canyon-took-industrial-acid-because-the-rock-looked-solid/ - Published: 2026-10-06T21:30:30.000Z - Updated: 2026-10-06T21:30:30.000Z - Author: Susan Price | ![Susan Price](https://c1uhcpoz192mv2zskt.b-cdn.net/891a6e76-4877-4452-9317-21cd9ea32dd5.png) | ![Marcus Grant](https://c1uhcpoz192mv2zskt.b-cdn.net/4b693653-34e7-4998-82f3-340ff4ea0934.png) | Susan Price & Marcus GrantOctober 6, 2026 | | --------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------- | ----------------------------------------- | | | | | | THE SHORT VERSION | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | • A California canyon took industrial waste for sixteen years.• The rock underneath was assumed solid, never measured.• Two wet winters pushed it through to the creek.• A whole town was taken off its wells. | | THE SETUP | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | The Stringfellow site sat in a narrow canyon on the southern slopes of the Jurupa Mountains in Riverside County, one mile above the community of Glen Avon. It opened in 1956 under a land use variance from the county planning commission, and from 1957 it ran as a Class I hazardous waste disposal site.Industry across southern California sent its liquids there: acids, chromium and cadmium from metal finishing and electroplating, DDT and TCE from pesticide production. They went into shallow unlined ponds covering three and a half acres, to dry out in the sun. Nozzles sprayed the liquid into the air to make that go faster. [Over 34,000,000 gallons](https://www.epa.gov/archive/epapages/newsroom%5Farchive/newsreleases/69d77f725f4bbb56852570d8005e1616.html?ref=core-sector.ghost.io) arrived in sixteen years.The canyon was the reason for the whole arrangement. It was taken that the rock beneath it was solid, so nothing would travel down or sideways, and that a concrete wall across the throat of it would hold whatever moved along the surface. The reasoning was geological, it was reasonable, and nobody had drilled it. | | THE TIMELINE | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Every row below comes from one document: [the record of decision](https://semspub.epa.gov/work/HQ/188275.pdf?ref=core-sector.ghost.io) the Environmental Protection Agency signed on 22 July 1983, which sets out what was known about the site and what had already been tried on it. Its appendix walks through each engineering report in turn, and through what each one found that the report before it had assumed.Read the fourth row first. In 1980, digging to inject sealing gel into what were believed to be fractures under the concrete wall, the crew found the wall was not keyed into rock at its ends at all. It stood on loose alluvial material, and waste had been moving underneath it.CASE FILEStringfellow, Riverside CountyEPA Record of DecisionSigned 22 July 1983THE ASSUMPTIONWHAT HAPPENEDTHE NUMBERSolid rock belowGround water downstream is already degrading1977No inflow from belowSeeps and springs appear in a wet winter1979300,000 gallons on siteTwo wet winters take it past 3,000,0001979The wall is keyed inExcavation finds it standing on loose alluvium1980No lateral movementA clay core wall is added downstream1981The wells will catch itThe leading part is already past them1983The canyon holds itSixteen years of liquid into unlined ponds34,000,000 gallons | | THE BREAK | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | Four things gave way in this canyon, and the ponds were the last of them.• **The rock was a conclusion.** The whole site rested on the view that the bedrock underneath was solid. By 1977 the engineers were reading ground water downstream and had begun to doubt it, and in 1980 an excavation settled the question.• **Dry weather did the measuring.** The belief that little water came in from below rested on where vegetation grew during a dry spell. In a wet winter, seeps and springs appeared in those same places.• **The wall stood on gravel.** The concrete barrier was never keyed into rock at its ends. A clay core wall and a gravel collection system had to be added downstream because the ground was not stopping sideways movement as had been thought.• **The catching came after.** In 1983 the leading part of the plume was already beyond the wells meant to intercept it. [Nearly 128,000,000 gallons of ground water](https://semspub.epa.gov/work/HQ/183343.pdf?ref=core-sector.ghost.io) had been pumped and treated by March 1996. | ![The unkeyed end](https://c1uhcpoz192mv2zskt.b-cdn.net/4eeeb3ac-9086-4dbf-b7a2-31028eefff0b.jpg) | WHO PAID | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Glen Avon, a community of about 10,000 people one mile downstream. In May 1972 a sample from the Glen Avon school water well came back with hexavalent chromium, and the well was closed. In 1969, 1978, 1979 and 1982, heavy rain sent the contents of the canyon down Pyrite Creek and into the streets.The people downstream organised before anyone else did. The Parents of Jurupa, led by Ruth Kirby, had been writing letters since the site opened in 1956\. In 1979 a second group formed, Concerned Neighbors in Action, [over 400 residents of Glen Avon](https://www.courtlistener.com/opinion/464866/united-states-of-america-v-jb-stringfellow-jr-concerned-neighbors-in/?ref=core-sector.ghost.io) led by Penny Newman, and asked to join the federal action as of right. The Ninth Circuit agreed in 1985.Since 1989 Glen Avon has taken its water from public utilities and no longer draws on the ground beneath it. | | THE PATTERN | | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | • **Ask what the containment is made of.** Here it was part concrete and part a view about rock. Only one of the two had been built.• **A dry season is not a test.** The reading that mattered was taken in the weather that showed least. Ask when a measurement was made, not only what it said.• **Find the joint, not the span.** The wall held. What did not hold was where it met the hillside, and nobody looked there until a digger did.• **Catching up is the long part.** Once a thing is moving, the equipment aimed at it has to sit where it will be, not where it is.I stood on a floor in 1990 where the overnight ceiling was a figure everyone could recite and nobody had ever pushed to see what would stop them.Of anything described as contained, ask which part of the containment was built and which part was concluded. Gold sits on whatever it sits on, and nobody has to have been right about the rock underneath for the weight to be the weight. |