"WEST, Texas -- Although the cause of the deadly blast at West Fertilizer Co. remains a mystery, a federal agency on Tuesday said the tragedy was preventable, citing shortcomings in existing regulations and standards at all levels of government."

"The Cowboy and Indian Alliance met Tuesday morning in front of the Capital to kick off a five-day protest against the proposed expansion of the Keystone XL Pipeline."

"A few casual words and the early release of some scientific data have cost the San Antonio region much-needed state funds to battle its growing air pollution problem. The misstep, which appears to have been unintentional, highlights the sensitivity of studying oil and gas pollution in business-friendly Texas."

"The Oregon Department of Transportation, the state’s rail safety overseer, says it will no longer ask railroads for reports detailing where crude oil moves through the state after The Oregonian successfully sought to have them made public."

"None of the tank cars currently in service carrying Bakken crude oil is adequate for carrying that product, a rail industry representative testified Tuesday, but until new federal regulations are completed, the use of inadequate cars will continue."

"Environmental groups are marking the 44th Earth Day on Tuesday with an assault on the Keystone XL pipeline, greenhouse gas emissions and other issues related to climate change."

"Plastic is everywhere, and with good reason: it's cheap, lightweight, and durable and can be turned into practically anything, from filmy plastic wrap to colourful children's toys to vital components in a computer or a heart valve. But scientists are discovering that plastic debris in the world's oceans, and in large bodies of water such as the Great Lakes, could be a far more serious environmental problemthan previously realized."

"Just a few miles from the spot where Enbridge Inc plans to build a massive marine terminal for its Northern Gateway oil pipeline, Gerald Amos checks crab traps and explains why no concession from the company could win his support for the project."

"Relatives and human rights groups urged Thai authorities on Monday to investigate the disappearance of an environmental activist who has worked to help ethnic Karen villagers report illegal activity at Thailand's largest national park."