The U.S. Environmental Protection Agency collected samples in the area Sept. 12 and 13, using a self-contained mobile laboratory to conduct real-time sampling and analysis. The agency tested for volatile priority pollutants such as benzene, toluene and xylene, which are commonly found in gasoline, as well as other industrial solvents.

The results showed that chemical concentrations in most areas fall below the Agency for Toxic Substances and Disease Registry´s health standards of concern. The agency cautioned that the results are the beginning of extensive sampling efforts and do not represent air conditions throughout the area.

Data the EPA gathered directly around a Murphy Oil Corp. crude oil spill at its Meraux, La., refinery showed elevated levels of benzene and toluene, which are associated with the petroleum release.

Hurricane Katrina damaged an 85,000-gallon tank, causing the spill, company officials said Sept. 4. Exposure for a year or longer at the levels measured would be required for health effects to be a concern.