"HOUSTON -- A federal agency investigating a deadly explosion at a Texas fertilizer plant told a Senate committee Thursday that regulation of the dangerous chemicals used in the industry fall under a 'patchwork' of standards that are decades old and are far weaker than rules used by other countries."

"President Barack Obama has vowed to tackle climate change in his second term, but so far has not acted to strengthen a tool that does not require backing from Congress - the National Environmental Policy Act."

"Just a day before President Obama announced he would only approve the Keystone XL pipeline if it 'does not significantly exacerbate the climate problem,' six environmental groups quietly lodged a protest with the State Department charging it would do exactly that."

"Exxon Mobil Corp.'s bid to shield from public view its inspection results for a shuttered pipeline that leaked at least 5,000 barrels of heavy Canadian oil sands crude in Arkansas this spring is galvanizing a debate over transparency and spill readiness that could affect the future of Keystone XL."

"Every year, people add 30 billion tons of carbon dioxide to the air, mostly by burning fossil fuels. That's contributing to climate change. A few scientists have been dreaming about ways to pull some of that CO2 out of the air, but face stiff skepticism and major hurdles. This is the story of one scientist who's pressing ahead."

"[Tuesday's] Supreme Court decision significantly expanding the rights of property owners to challenge the terms of land-use permits has puzzled environmental law experts and has liberal groups accusing the conservative justices of judicial activism."

"The U.S. Environmental Protection Agency has concluded that current testing of hormone-altering chemicals is adequate for detecting low-dose effects that may jeopardize health."

"Following the recent federal decision to list captive chimpanzees as an endangered species, the National Institutes of Health announced Wednesday it would retire the majority of the approximately 360 government-owned chimpanzees currently held in laboratories."

"Thunderstorms that brought significant rainfall to the northern U.S. Midwest early this week, accompanied by warm temperatures, bolstered growth prospects for recently planted corn and soybean crops, an agricultural meteorologist said on Wednesday."

"The Energy Department is moving toward abandoning a half-built factory that has cost $3.7 billion so far and was intended to make reactor fuel out of plutonium from retired nuclear bombs — part of an agreement with Russia to shrink the world’s supply of nuclear bomb fuel after the cold war."