Aluminum hydroxide coatings on fuel elements stored in aluminum canisters in K West Basin were measured in July and August 1998. Good quality data was produced that enabled statistical analysis t o determine a bounding value for aluminum hydroxide at a 99% confidence level. The updated bounding value is 10.6 kg per Multi-Canister Overpack (MCO), compared t o the previously estimated bounding value of 8 kg/MCO. Thermal analysis using the updated bounding value, shows that the MCO generates oxygen concentrations that are below the lower flammability limits during the 40-year interim storage period and are, therefore, acceptable.