Tenneco said it will write off two projects.

As a result of writing off substantially all of its investment in the Great Plains coal gasification project and the Cathedral Bluffs shale oil project, Tenneco said, it will take a one-time after-tax charge of about $240 million against third-quarter earnings. Tenneco said it decided to take the charge because of falling world oil prices, the Energy Department’s refusal to support the Great Plains project and a probable lack of sufficient assistance by the Synthetic Fuels Corp. for the Cathedral Bluffs project.