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Conservation Issues of the Ventana Chapter | santa cruz wide
Toxic trouble in Davenport
December 2008
Clearcutting in the Sierra Nevada
Ten times the allowable amount of chromium-6 in Davenport from the Cemex plant brought Erin Brockovich to town. The environmental investigator believes there are no safe levels of chromium-6. Photo by Jodi Freidiani.

by Kristen Raugust

On October 3, 2008, the County announced that chromium-6 (Hexavalent chromium) had been detected in Davenport, 10 times the allowable amount, along with the worrisome news that this toxin may have been emitted for a number of years. The Monterey Bay Unified Air Pollution Control District had decided to conduct unannounced tests in June, July, and August 2008 after high chromium-6 levels were detected at a cement plant in Riverside, California. The results of this testing required the Monterey Bay Unified Air Pollution Control District to issue a Prop. 65 notification to the Board of Supervisors and the County Health Officer. A Public Health Advisory for the Davenport Area was issued the same day.

The cement plant in Davenport was built by Portland Cement Company in 1905. Many companies have owned it over the years since then, with its current owner being Cemex Corp of Mexico. In 1905, little was known about environmental health problems resulting from cement plant emissions. We now know that cement plants emit dust and substances that can cause cancer and other health problems.

Many environmental groups, including the Sierra Club, have been battling such plants over emissions, including mercury, which can cause birth defects and neurological problems in small children. The Davenport Cemex plant was already on environmentalists’ radar screen for its seriously high mercury emissions. In 2005 (the most recent year for which a report was made), the Cemex plant emitted 170 pounds of mercury, making it one of the biggest emitters of mercury nationwide. Under pressure from Miriam Rotkin-Ellman of the Natural Resources Defense Council, the Environmental Protection Agency conducted tests for mercury in Davenport last summer.

Cement-making operations were already shut down in Davenport at the time of the health advisory, due to low sales. The Cemex plant was advised by the County to remain shut until better understanding of the extent and control of the chromium-6 emissions was achieved.

At a Board of Supervisors meeting on October 7, the public was assured that it would be apprised of any new data as soon as it became available. Satish Sheth, head of manufacturing on the U.S. west coast for Cemex, said the plant would cease using mill scale and steel slag in the future, since these by-products of steel manufacture, in use since 2001, are suspected to be the source of the chromium-6.

Ironically, it was the Air Pollution Control District that had repeatedly assured the community of Davenport that the introduction of slag was safe, despite numerous concerns. Sheth said Cemex would replace the mill scale and steel slag with iron ore when manufacturing resumed. He also said Cemex would implement strict fugitive dust control procedures. Fugitive dust from loading operations and the cement kiln dust pile is believed to be responsible for the spread of chromium-6 in Davenport.

Santa Cruz County Environmental Health confirmed at the October 7 Board of Supervisors meeting that tests of drinking water showed a non-detect of chromium-6, although the last water test was done on August 28, 2007, leading to the belief that the problem is possibly just airborne. Additional water samples, taken from Mill Creek, San Vincente Creek, and Pacific Elementary School on October 7, also showed a non-detect level at a limit ten times less than the California Drinking Water Standard.

Attending the Supervisors meeting were parents of children from Pacific Elementary School which is right in the plume path of Cemex’s smoke stack. Many concerned residents urged medical testing to find out human exposure potential. Others urged that trucking and movement of the contaminated, stored cement and cement kiln dust cease until more data was gathered.

The day after the meeting, Santa Cruz County Environmental Health representatives went door to door in Davenport to issue a Health Advisory until test results showed air quality had returned to safe levels.

At the October 21 Board of Supervisors meeting many residents complained that real data was not yet available. They also strongly urged that shipping operations at the plant cease until test results were available and procedures to reduce chromium-6 contamination were in place. The Supervisors assured the residents that information would be available within days. The Board also indicated that a competent contractor for the air testing, Copeland Consultants, had been retained. This choice has since raised concern about the firm’s impartiality because of the prior associations of one of its consultants.

Despite residents’ very real concerns regarding fugitive dust, the Board did not require Cemex to halt shipping. However, Cemex voluntarily suspended shipping until test results were available. Data from continued air testing by the Air District before Copeland was hired, was finally available on October 25, showing the chromium-6 level had dropped below the allowed standard. This finding may have been due to Cemex’s suspension of shipping of the contaminated cement.

The new contractor set up testing stations in and around Davenport including a 24-hour air monitor inside the school and one on the playground. New testing began November 1. This monitoring system should provide more accurate testing and will include surface wipe sampling.

Other tests taken before Copeland was hired showed a further drop in chromium-6 from earlier October results. Even though these preliminary tests have indicated a general drop in chromium-6, some days have spiked dramatically and need to be studied and investigated as to the exact cause.

Nationally-known environmental investigator Erin Brockovich came to Davenport on November 3 and met with residents. She explained that she wanted to share her expertise about chromium-6 and expressed her concern about all the other toxins that emanate from the plant. Brockovich, however, believes, as do many scientists and environmentalists, that there are no safe levels of chromium-6.

Brockovich noted discrepancies in the reporting of toxic emissions and was somewhat skeptical of the data since Cemex oversees the testing. She encouraged residents to talk to each other and compile information about their experiences with dust, smell, and their health. She also provided health questionnaires to be filled out and returned.

On a path to restarting the plant, Cemex was granted a temporary 48-hour permit on November 12 to carry out a test grinding of the contaminated clinker. (Clinker is hardened cement as it comes out of the heated manufacturing process and is ground into cement dust. Reducing agents ferrous sulfate and stannous sulfate were added to reduce chromium-6 emissions.)

The test-grinding results came back with levels of chromium-6 safe enough (according to the Air District) for Cemex to plan a full-scale production test. After the test the plant will shut down as the monitoring data are evaluated. Cemex plans to restart the plant in January if test results are positive.

Residents and parents of school children continue to urge the County not to let production begin until the exact source of the chromium-6 can be pinpointed and absolute assurances can be made for their and their children’s safety.




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