Environmental Exposure Surveillance in a Combat Theatre

1. Environmental Exposure Surveillance in a Combat Theatre Coleen Baird , MD, MPH US Army Center for Health Promotion and Preventive Medicine I have no disclosures to make

2. Range of Exposures in Deployed Settings • Occupational/Personal Sampling- Individual Exposures • Actionable for surveillance or other • Archive for general information, document “negative exposure” • Ambient Sampling: Exposure Not Clearly Linked to an Individual • Epidemiological formation of cohort • Population level risks • Potential Exposures- based on defined “reasonable probability” • May be actionable • May lack sampling information

3. Air Exposure Concentration ‘Continuum’ multiple low-level exposures, continuous, long-term Terrorist attack; accidental release industrial operations; accidental releases Single exposure Lifetime exposure past practices; uncontrolled emissions mg/m3 ug/m3 EPA: IDLH TLVs ambient air standards severe significant minimal

5. Refined Exposure Assessments • Exposures identifiable to an individual or Similarly Exposed Groups (SEGs) • Exposed by nature of location or occupation such as asbestos, lead, burning trash • Requires an exposure assessment and identification of group/SEG constituents • Relatively easy to put into medical records • May require individual surveillance

7. Ambient or Routine Exposures • Greater likelihood of being “low” • Lower likelihood of health effects • Cohorts more readily “defined” thru available data sources • Exposures to those in defined cohort more variable

8. Ambient Environmental Monitoring • Air: PM/metals/volatile organics in the ambient environment of the sampler • PM levels high, but variable • Most other findings rare • Large population at risk/Base camp level • Exposures not uniform • Movement • Distance from sampler • Indoors • Convoys/Trash

9. Ambient Environmental Monitoring Challenges linking location data (population at risk) to health data Outcomes may be diluted due to misclassification of exposure, non-specific outcomes Data not readily interpretable by most providers

10. Incident or Unplanned Events • Greater likelihood of being “high” • Greater likelihood of health effects • Lower likelihood of actual measurement • Typically involve fixed but hard to define cohort

11. Principles of Medical Surveillance Under the NRP • Maintain the physical and mental health of responders/Identify new clinical entities/Assess adequacy of PPE • Participation should be confidential and voluntary • There should be a centralized mechanism to capture data related to individual and collective exposures

12. Principles of Medical Surveillance Under the NRP • Creation of a registry of workers at the site • Exposure assessment strategies should be developed and implemented to protect workers and guide interventions • Each individual should receive detailed and interpreted biomedical and exposure data • Risk communication needs to be an integral part

14. Enhanced exposure analyses UNCLASSIFIED

15. 2003 Sulfur Fire • Multiple samples taken over weeks at various locations* • Health care provided on site by a special team* • Documented in medical record* • Exit physical standardized for firefighters • Roster of firefighters obtained and archived* • Health outcome analysis*

16. Long Term Follow-up • Defined cohort • Small numbers • Poorly defined cohort • Exposures variable • Weak exposure/ weak inclusion • Misclassification bias • Rare outcomes/unusual coding

17. Lessons Learned • Traditional IH surveillance possible in deployed setting if equipment/skill sets available • Ambient sampling has proven difficult to integrate into routine medical care • “Incident driven” events pose a challenge for data collection, and potentially for long-term follow-up