ATSDR Exposures Survey (ACE)
Page originally published 10/18/2024. Last updated 9/3/2025.
From October 21 - November 22, 2024, the Centers for Disease Control and Prevention (CDC) Agency for Toxic Substances and Disease Registry (ATSDR) and the County of San Diego conducted an online survey related to sewage and pollution in the Tijuana River Valley. This survey, called an Assessment of Chemical Exposures, or ACE, was another opportunity for people affected to share their experiences and help public health and emergency response leaders better understand the health status and needs in the South Region of San Diego County.
On this page:
What is an ACE?
The Assessment of Chemical Exposure (ACE) is an online survey carried out by the federal ATSDR. It is a way for local and state public health and disaster response agencies to quickly assess how many people were exposed to hazardous agents (chemical, radiological, nuclear, biological or other hazardous agent), and if they are experiencing symptoms or have any immediate needs.
An ACE may be requested when:
- A harmful substance was released at levels that may cause acute human health effects.
- People are exposed and experienced acute health effects.
How was the ACE Done?
The ACE asked people who may have been exposed detailed information on:
- exposure history,
- symptoms experienced,
- who was exposed,
- health services used,
- needs resulting from the exposure,
- medical history,
- how people received information about the release, and
- health impacts on pets.
What is the Data being Used For?
Results from ACE will help public health and emergency response
leaders:
- assess impact of the release on individuals as well as the community,
- direct the public health response,
- target outreach to prevent similar incidents,
- assess the need to modify emergency response procedures, and
- identify a group of exposed people that may need to be followed-for long-term effects.
How is This Different from the CASPER Survey?
The Centers for Disease Control and Prevention (CDC) worked with the County to conduct a Community Assessment for Public Health Emergency Response, or CASPER. This was done by:
- Using a two-stage sampling method designed to pick a representative number of households to interview in a certain block (cluster).
- Interviewing the randomly selected household face-to-face.
- Asking about the household’s health concerns, experiences, and impacts from sewage and pollution in the Tijuana River Valley.
The ACE was an online survey that any eligible individual could take.
- The goal was to have at least 2,000 complete questionnaires.
- People working or visiting the area for recreation were also eligible to complete the ACE.
- Parents could answer for children under 18 years of age.
- The areas included were expanded from Imperial Beach, Nestor, San Ysidro, and also included Otay Mesa West, Silver Strand, and Coronado.
Both CASPER and ACE are assessments key to identifying community
health concerns and prioritizing solutions.
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How to use this dashboard
- To see the data for a specific category, click on one of the tabs at the top of the dashboard: About, Demographics, Household Awareness and Experiences, Disruptions to Household Life, Household Opinions and Beliefs, Communication Preferences, Physical Health, Mental and Behavioral Health, and Individual-level Mental Health.
- After choosing a category, the page will show a graph with results from specific survey questions from the chosen category. Use the "Show/Hide Data Table" button under each graph or hover your mouse over the graph to see a pop-up that displays more data and descriptions.
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How to download the ACE dashboard report
- To download the report, open the dashboard.
- Once the page opens, look for the “Download Report” button. Click the button to download the full report to your device.
- If the download doesn’t start, try refreshing the page or using a different internet browser.
County of San Diego:
- CASPER and ACE Health Surveys Fact Sheet | Spanish (Español)
- Tijuana River Valley Sewage Emergency: Assessment of Chemical Exposure (ACE) Results Presentation
- What the County is Doing
- San Diego Access Crisis Line: Mental health resources are available for anyone feeling emotionally affected by the Tijuana River Valley sewage crisis by calling 1-888-724-7240 or 988.
County News Center:
- Tijuana River Valley Sewage Community Survey Results Complete (July 8, 2025)
- County Hears from More than 2,100 People on Impacts of Tijuana River Valley Sewage (November 25, 2024)
- County Hears from Nearly 2,000 People on Impacts of Tijuana River Valley Pollution (November 15, 2024)
- Tijuana River Valley Pollution Survey Completion Rate Passes 1,000 Mark (November 4, 2024)
- A Second Federal Tijuana River Valley Health Survey Starts Today (October 21, 2024)
- County Expands its Health-Focused Response to Tijuana River Valley Sewage Crisis (September 5, 2024)
Centers for Disease Control and Prevention:
Send an e-mail to the Epidemiology Unit for more information.
