VIII. Conclusions

This PHA evaluates potential inhalation exposures to air contaminants released from the Navy property on Vieques. ATSDR has been examining, and continues to examine, potential exposures to contamination from other environmental media (e.g., drinking water, soil, and food products). After completing its evaluations, ATSDR will assess the public health implications of the cumulative or overall exposures from the other potential pathways the agency has considered.

For the air exposure pathway, ATSDR concludes the following:

• As of the writing of this report, more than 400 valid air samples have been collected on Vieques on days when bombing exercises did not take place. All samples have shown that levels of particulate matter are much lower than health-based air quality standards. Thus, wind-blown dust from the LIA is not a health hazard on days without military training exercises.
• Military training exercises using practice bombs release various contaminants to the air, but the available sampling data indicate that ambient air concentrations of particulate matter, metals, and explosives did not reach levels that present a public health hazard.
• The past military training exercises involving live bombs released many contaminants to the air, but most dispersed to extremely low concentrations over the 7.9 miles that separate the center of the LIA from the nearest residential areas of Vieques. ATSDR's best estimates of ambient air concentrations suggest that past exposures during the live bombing exercises were at levels below those associated with adverse health effects. This conclusion is based entirely on modeling results and therefore involves some uncertainty, though ATSDR believes its approach to evaluating the live bombing exercises provides a reasonable account of past exposures.
• Though open burning and open detonation operations to treat unused munitions and unexploded ordnance have undoubtedly released contaminants to the air, these operations account for a small fraction (<10%) of the high explosives that were previously detonated during military training exercises using live bombs. ATSDR's modeling analysis indicate that emissions from the open burning and open detonation operations do not cause levels of pollution that could present a public health hazard in the residential areas of Vieques.
• Residents of Vieques are not exposed to levels of environmental contamination that could present a public health hazard, whether chemical or radiological, as a result of the Navy's limited past use of depleted uranium penetrators during military training exercises. Further, no adverse health effects are expected to result from the Navy's usage of chaff, because this material disperses considerably between the time it is released (several thousand feet above sea level) and the time it settles to the ground.
• Overall, ATSDR found that the residents of Vieques have been exposed to contaminants released during the Navy's military training exercises, but these exposures are far lower than levels known to be associated with adverse health effects. As a result, ATSDR finds that the air exposure pathway at Vieques presents no apparent public health hazard.

Aware of the level of community health concerns at Vieques, ATSDR is committed to reviewing additional air sampling data and health outcome data as they become available. The Public Health Action Plan (Section IX) outlines future actions that various agencies will take to evaluate environmental health issues at Vieques.