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Crash of the B-29 on Travis AFB, CA
August 5, 1950

Excerpt from the Public Health Assessment concerning the B-29 Crash Site from the Agency for Toxic Substances and Disease Registry (ATSDR). The ATSDR is an agency of the U.S. Department of Health and Human Services, whose mission is to serve the public by using the best science, taking responsive public health actions, and providing trusted health information to prevent harmful exposures and disease related to toxic substances. This is not the entire report about Travis AFB, but just the part concerning the crash site therefore section, subsection and paragraph numbering will be off.





ATSDR's public health assessments concentrate on evaluating the likelihood of exposure to contaminants in the environment. Chemical contaminants disposed or released into the environment at Travis AFB have the potential to cause adverse health effects. However, a release does not always result in exposure. People are only exposed to a chemical if they actually come in contact with the chemical. Exposure may occur by breathing, eating, or drinking a substance containing the contaminant or by skin (dermal) contact with a substance containing the contaminant.

Exposure does not always result in adverse health effects. The type and severity of health effects that may occur in an individual from contact with a contaminant depend on the exposure concentration (how much), the frequency and/or duration of exposure (how long), the route or pathway of exposure (breathing, eating, drinking, or skin contact), and the multiplicity of exposure (combination of contaminants). Once exposure occurs, characteristics such as age, sex, nutritional status, genetics, life style, and health status of the exposed individual influence how the individual absorbs, distributes, metabolizes, and excretes the contaminant. Together these factors and characteristics determine the health effects that may occur as a result of exposure to a contaminant.

In this section we evaluate the possible ways that people can be exposed to contamination ("pathways") at Travis AFB. We do this by examining the possible exposure situations to determine whether people in the community are exposed to (or in contact with) the contamination. We then look at whether that exposure may cause adverse health effects.

ATSDR concluded that one exposure situation currently poses an indeterminate public health hazard. There are not enough environmental data to determine whether there are sufficient contaminants in edible fish in the duck pond and whether people are consuming enough fish from this pond to present a health hazard.

Five other exposure situations pose no apparent public health hazard because the exposures would be infrequent, exposure is unlikely, or the contaminant concentrations are too low to present a possible hazard. Five other situations pose no public health hazard because no contaminants were found or because no exposures have occurred. Table 1 shows these situations.

Table 1: Travis AFB -- Evaluation of Health Hazard Situations

Table 1: Travis AFB - Evaluation of Exposure Situations
B-29 crashradionuclidesplane crashsurface soilarea of crash, adjacent to present family campground, NW quadrant of baseinhalation, dermalN/Acrash occurred in 1950No Public Health HazardATSDR Health Consultation found no evidence of public health hazard. Crash did not contribute radionuclides to environment.

Table 2 summarizes ATSDR's public health conclusions for the exposure situations identified at Travis AFB. Following sections contain detailed discussions of each situation. Additional information describing ATSDR's conclusion categories is provided in Appendix D.

Table 2: Summary of ATSDR's Public Health Conclusion for Travis AFB.
Conclusion CategorySituation
No Public Health Hazard- Drinking or Other Exposure to Groundwater at:
     1) Fire training Area 4;
     2) Landfill 2; or,
     3) Bldg. 1125
- B-29 Crash Site
- Grazing Areas 7,8, Landfill X

III. No Public Health Hazards

B. 1950 B-29 Crash Site

On August 5, 1950, a B-29 bomber crashed shortly after takeoff. The impact occurred in the northwestern portion of Travis AFB, as shown in Figure 9. About 20 minutes after the crash, 6,700 pounds of explosives on the plane detonated. The explosive, cyclotrimethylenetrinitramine ("RDX") is an explosive used in nuclear weapons, as well as conventional artillery. Nineteen fatalities and numerous injuries resulted from the explosion.

The B-29 was carrying a small quantity of depleted uranium. According to Air Force documents, depleted uranium, with very low radioactivity levels, has been commonly used as ballast in nuclear weapons. Its high density provided appreciable weight while occupying relatively less space than less dense materials, and therefore allowed for the construction of smaller weapons. Also, small amounts of radium would have been present as the luminous material in aircraft dials and gauges.

According to reported Air Force procedures at the time, while in transit over United States territory, the weapons-grade radioactive material was transported in one airplane while the nuclear weapon (trigger mechanism, etc.) was transported in a second airplane. The crash involved the second instance, that is, the airplane carrying the weapon, but not the radioactive material. In 1994, radionuclides detected in sampling and analysis by the Air Force were found at levels attributable to naturally-occurring materials in the environment (e.g., soil and rocks). Surface soil, subsurface soil and groundwater samples were collected from the vicinity of the crash. Sample sites were chosen by taking into account the prevailing wind directions for soil samples, and the groundwater flow for groundwater samples.

The following table depicts the average radiation levels found in soil in comparison to average background levels for northern California for the same radionuclides.

In the course of the environmental evaluation, three groundwater monitoring wells were sampled, twenty-six subsurface soil samples were collected, and eighty surface soil samples were collected. The groundwater sampling and analysis found no radionuclides above the levels occurring naturally in the area. Based on the results of the environmental sampling, it is not likely that radioactive contamination was released as a result of the crash of the B-29. Therefore, in terms of possible exposure to radionuclides carried onboard the airplane, this crash site does not present a public health hazard.

Table 3: Radionuclides in Soil at the Site of the B-29 Crash (4)
RadionuclideLevel Detected (picoCuries per gram of dry soil- pCi/g dry)Background Level
pCi/g dry
Plutoniumlevel too low to measure or not present0.01


In preparing this Public Health Assessment (PHA), ATSDR relies on the information provided in the referenced documents. The Agency assumes that adequate quality assurance and quality control measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting. The validity of the analyses and the conclusions drawn in this document are determined by the availability and reliability of the referenced information.

The majority of the environmental data presented in this public health assessment are from the Remedial Investigation (RI) preliminary data. Data collection and analysis are conducted in consultation with EPA and California environmental regulatory agencies. Generally, the methodology used in the RI activity is appropriate for characterizing contamination at Travis AFB. Additional information collection is planned during completion of RI activities. If this information suggests previously undetected concerns about potential public health hazards, ATSDR will conduct a re-evaluation of that information. Conclusions and Recommendations of this PHA will be modified if appropriate and necessary.


Public health concerns were investigated by ATSDR through meetings, correspondence, telephone conversations and technical information from Travis AFB, EPA, and state agencies. Extensive outreach programs have been conducted by these agencies. Specific community public health concerns have been identified in regard to groundwater contamination, possible exposure to contaminants from soil gas under the trailer park, the potential for exposure resulting from contamination in Union Creek, the B-29 crash and the occurrence of "horse swelling" incidents that occurred in 1985 - 1987. The evaluations of these situations are presented in the body of this document. As discussed in the environmental evaluations sections of this document, there are no public health problems resulting from these incidents.


We did not evaluate health outcome databases because people were not exposed to site contaminants at levels that would result in public health hazards.


Possible issues related to children's health were evaluated in relation to the trailer park, Union Creek and the B-29 crash. These situations were found NOT to have an adverse impact on children's health. The exposure situation at the Duck Pond is considered unlikely to result in a health hazard, since its use as a frequent, regular and long-term source of fish is not likely, but is indeterminate, due to a need for further information.

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