The SCAQMD, in response to a request from the County of Los Angeles Fire Department Health Hazardous Materials Division (LACFD), analyzed two (2) canister samples collected inside the SoCalGas Company’s Aliso Canyon facility close to the leaking well (SS-25).   The SCAQMD provided the sample collection canisters to LACFD and the samples were collected on site by staff from the firm of Boots and Coots (SoCalGas’ Contractor) in the area near the leaking well.  Due to safety and practical reasons, samples could not be collected directly in the gas plume, but were collected as close as possible, about ten (10) feet downwind (Southwest) of the SS-25 well site.  These two grab (instantaneous) samples were collected within a few minutes of each other. Chain of custody was continuously maintained for both samples. In addition, the SoCalGas Company also collected a third sample at the same location for their information. 

Samples were analyzed in the SCAQMD laboratory (see laboratory results).  Although the two samples were collected at the same location and one right after the other, there are differences in what was captured and the laboratory results.  While there are no notations recorded on the sample custody/analysis request form as to ambient conditions at the time of sampling, one explanation of the differences in results could be the influence of variation in winds that are commonplace in the area. 

It is important to note that the concentration levels of various compounds measured in these samples do not represent the levels to which the community is exposed, and that their concentration levels are expected to decrease significantly as the gases are dispersed in the atmosphere as they travel downwnd to the community. 

For the results of air samples taken in the community and health risks associated with exposure to such concentrations please refer to the Ambient Air Analysis and Health Impacts Estimates pages, respectively.