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# ‘Rock’ solid information
- URL: https://www.smdp.com/rock-solid-information-editor/
- Published: 2007-01-29T16:00:00.000Z
- Updated: 2026-10-23T23:55:19.000Z
- Author: Guest Author
- Tags: Opinion, Santa Monica, #archive-import

*By M.J. Coplan Massachusetts registered professional engineer*

(Re: “On the water front,” Jan. 19, page 1) Ninety-two percent of U.S. fluoridated water is treated with fluosilicic acid, a by-product collected in processes used to convert “phosphate rock” into phosphate fertilizer and recover uranium also in that rock.

*Originally published in the Santa Monica Daily Press print edition on January 29, 2007.* [Read the original PDF.](https://s3.us-east-1.amazonaws.com/smdp%5Fbackissues/012907.pdf?ref=smdp.com)