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Health Topics > Sierra-Crete Task Force

Sierra-Crete Task Force

Draft Minutes
June 26, 2002

Task Force Members

Present: Brian Bornstein, City of Brentwood; Joe Brandt, City of Antioch; Dr. Wendel Brunner, Contra Costa Public Health Director; Julie Bueren, Contra Costa Public Works; Brenda de la Ossa, staff to Donna Gerber, Contra Costa Supervisor District III; Martha Harnly, California Department of Health Services; Sara Hoffman, Contra Costa CAO's Office; John Fuller, City of Pittsburg; Federal Glover, Contra Costa Supervisor District V; Annette Guiseppi-Elie, DuPont; Suzanne Murray, City of Oakley; Charles Salocks, California Office of Environmental Health Hazards Assessment; Nasser Shirazi, City of Pittsburg;

Absent: Mike Yeraka, Contra Costa Water District; Dave Berry, California Department of Toxic Substances Control

Staff: Paul Andrews, Michael Kent, Dana Harvey, Contra Costa Health Services

Members of the Public: Gary Bosch, Boornazian, Jensen & Garthe; Bill Faisst, Brown and Caldwell; Will Harper, East Bay Express; Kay LaCour, Cooper, White & Cooper; Ben Strumwasser, Public Affairs Management; Stephen Welch, Archer Norris; Richard Wenning, Environ;

1. Introductions

Dr. Brunner called the meeting to order at 10:30, introductions were made, and the agenda was adopted without change. David Berry was unexpectantly unable to attend due to being called to testify at a trial.

2. Brief History of the Issue

Annette Guiseppi-Elie of DuPont gave a brief overview of the history of the issue. She said that about three months ago DuPont tested Sierra-Crete and found it contained low levels of dioxins in the range of 65 -- 300 parts per trillion on a WHO-TEQ basis, but the dioxins found in Sierra-Crete were not the most toxic forms of dioxin. In response, they collected and analyzed samples of Sierra-Crete, residuals on the surface of roads where Sierra-Crete was used, and residuals on the surface of roads where Sierra-Crete wasn't used. They then conducted a risk assessment for road construction crews and residents. They concluded the levels of dioxins found do not pose a health threat. They presented their results to the State Department of Toxic Substances Control on May 20, 2002, representatives of jurisdictions where Sierra-Crete was used on May 24, 2002, and to the Central Valley and San Francisco Bay Regional Water Quality Control Boards in additional meetings.

A Question and Answer period followed the presentation:

Q: Why was Sierra-Crete tested for dioxins in the first place?

A: DuPont realized that the chlorine in the process could cause the formation of dioxins. It was tested at active sites where the process was still being conducted.

Q: Are there other places that Sierra-Crete is used?

A: Not in the US because in was difficult to market, the plant was shut down and it is not made anywhere else. But it is used in Taiwan.

Q: Are the dioxins formed by naturally-occurring organic material in the ore?

A: Yes, and in the coke used in the manufacturing reaction process.

Q: Where is information available about Sierra-Crete on the Internet?


At this point Joe Brandt from the City of Antioch provided some additional information about the use of Sierra Crete in Antioch. Antioch first tested it on L Street and then used it on about 18 miles of roads between 1990 and 1995. In 1994 they started to notice a residue on street surfaces and thought it was calcium chloride leaching onto the surface. In 1996 they stopped accepting roads made with Sierra Crete from subdivisions for city maintenance because of poor quality, triggering lawsuits. Pipes passing through the Sierra Crete have also corroded, and there are lawsuits about that issue as well. He thinks it has also caused failure in the asphalt, but that has not been determined yet.

Q: What was the regulatory approval process for being able to mix Titanium Dioxide manufacturing wastes with Portland cement to make Sierra-Crete?

A: None of the DuPont representatives present knew the answer, however Charles Salocks said that the Department of Toxic Substances Control would only have been involved if the waste material had been a hazardous waste. Joe Brandt clarified that Sierra-Crete itself is not classified as a hazardous waste.

Q: Were the chemical properties of Sierra-Crete tested before it was used?

A: Yes, and this information is available.

Q: Was the soil or the groundwater beneath the Sierra-Crete tested for dioxins?

A: No.

Q: Are the problems limited to the roads where Sierra-Crete was used in Antioch?

A: Joe Brandt responded that problems have been found in Bay Point, and Oakley, and that maybe enough time hasn't passed yet for the problems to appear on the roads in elsewhere.

3. Purpose and Scope of Taskforce

Supervisor Glover felt the purpose of the taskforce was to identify all the locations where Sierra-Crete was used, review the risk assessment that was done by DuPont, assess the need to conduct further testing, and identify who would be responsible for any actions that result from the analysis.

Dr. Brunner added that he felt it was important that the taskforce work with the community and all the stakeholders to determine what testing needs to be done to be assured the community is safe, and to determine what mitigations need to be put in place for workers who may come in contact with the Sierra-Crete. He felt that all the work the taskforce does needs to be communicated well to the public, and that all work needs to be done at the taskforce level.

Annette Guiseppi-Elie wanted clarification on who is considered a member of the taskforce. She also suggested a step-wise approach to the work: 1) evaluate the risk assessment and then 2) determine if more testing is needed.

Joe Brandt wanted to be sure that the risk to the workers that have already worked with Sierra-Crete is examined. Annette Guiseppi-Elie mentioned that had been done in the risk assessment.

Brenda DeLaOssa wanted to make sure the taskforce considered the impact on stormwater in the analysis. Dr. Brunner agreed that water quality is important, so it will be important to include the Regional Water Quality Control Boards in future decision-making. Annett Guiseppi-Elie mentioned that DuPont did look at stormwater issues in a supplemental study that was presented to the Regional Water Quality Control Boards, and that they were comfortable with the results.

Dr. Brunner summarized that the purpose and the scope of the taskforce will be to evaluate the risk assessment done by DuPont, identify additional samples needed to evaluate the health risks and stormwater risks, and adjust the risk assessment to take into consideration the results of the additional data. He added that the taskforce would not be involved with the issues concerning the physical properties of the Sierra-Crete or the roads. Membership of the committee will be limited to those that were invited to this meeting and the Regional Water Quality Control Boards, but all meetings will be open to the public.

4. Review of the Risk Assessment

Richard Wenning gave a brief overview of the risk assessment. Environ used California and Federal EPA guidelines in developing the risk assessment. They took 10 samples of Sierra-Crete from the Oakley facility and one from underneath a public road. They tested 16 areas of Antioch for residue on the surface of streets where Sierra-Crete was used both randomly and in a biased manner using wipe samples to collect the material. They also collected samples off of roads where Sierra-Crete wasn't used. In all they took 91 samples that were analyzed for a broad range of dioxins.

The risk assessment found that all exposures to dioxins from the roads to both workers and residents was less than 2% of total exposure, no cancer health risk exceeded one in a million, and no non-cancer thresholds were exceeded.

They looked at 2 Antioch creeks, a reservoir and a lake for possible surface water contamination issues and also didn't see any significant impacts.

A Questions and Answer period followed the presentation:

Q: Does the risk assessment present only the percentages, or is the raw data also presented?

A: All the data is presented.

Q: The samples were taken in April and May, but the surface residue is greatest in the hot summer months. Does the risk assessment take this factor into account?

A: No

Q: Only one sample of Sierra-Crete was actually taken from under a public road, the rest from a test area at the DuPont manufacturing site in Oakley. Was this representative?

A: Remember that the levels of dioxin on the surface are lower the levels found in the Sierra-Crete itself. Joe Brandt noted that Sierra-Crete was not manufactured under very controlled conditions, therefore the concentration of dioxins may vary from batch to batch.

Q: Is there a list of the different batches of Sierra-Crete that were manufactured and where each batch was used?

A: Not presently, but Annette Guiseppi-Elie indicated that she would see if such information is available. (Action Item)

Q: Is it possible that people could be re-exposed to Sierra-Crete in the future.

A: Yes, during repairs.

Q: Is there a map of all the locations where Sierra-Crete was used?

A: Most of the sites in Antioch are known and a map will be put on the web, but a map needs to be developed for the other areas of the County where it was used.

5. Evaluation of Further Needs and Data Gathering.

Dr. Brunner felt that more sub-surface samples of Sierra-Crete and more surface samples were needed from all the affected communities.

Martha Harnly felt the data from the additional samples should be plugged into the Risk Assessment model, once it has been reviewed and the methodology agreed upon by everyone.

Dana Harvey stressed that independent sampling and testing is needed as well as an independent review of the Risk Assessment. The soil and ground water under the areas where Sierra-Crete was used needs to be tested for dioxins.

Annette Guiseppi-Elie said that DuPont want the process to be as transparent as possible.

Charles Salocks was not sure what his agency's availability would be to review the Risk Assessment.

Dr. Brunner asked all the jurisdictions to identify the areas where Sierra-Crete was used.

Julie Bueren agreed that the Contra Costa County Public Works Department would compile the data on where Sierra-Crete was used. (Action Item)

Charles Salocks felt more background samples of the surface and subsurface areas are needed, as well as samples from beneath the Sierra-Crete. In addition to wipe samples, consideration should be given to vacuuming surface areas for particulates.

Supervisor Glover asked Contra Costa Health Services to take the lead in developing the sampling plan. (Action Item)

Joe Brandt informed the Group that the City of Antioch is planning to drill about 30 holes in pavement where Sierra-Crete was used to conduct strength testing next month, and perhaps dioxin samples could be taken at the same time.

Dr. Brunner indicated that he would like the State Agencies to take a quick look at the Risk Assessment and then determine if a consultant needs to be hired to do a in-depth review. (Action Item)

6. Public Involvement

Michael Kent suggested that the public be informed each step of the process. An attempt should be made to find public members to participate in the development of the sampling plan. (Action Item) Public meetings should be held before and after the additional sampling is done to keep the public informed and to provide them with an opportunity to ask questions. There was general group agreement to this approach.

The meeting closed at 12:30 with an understanding that Michael Kent would prepare minutes, and distribute them to all members and guests.

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