"There's a heated debate over the use of antibiotics in farm animals. Critics say farmers overuse these drugs; farmers say they don't. It's hard to resolve the argument, in part because no one knows exactly how farmers use antibiotics."

"Mercury found in high levels in deep Pacific Ocean fish such as swordfish has a chemical fingerprint, and it implicates coal-burning power plants in Asia, according to a new study."

"MONTREAL — Quebecers should be worried that it took 15 years for officials to clue into the fact that a Pointe-Claire company had a yard full of toxic materials, says one environmental expert, and the public should be demanding more transparency in the wake of the discovery."

"An Oakland watchdog group has sued four companies and plans to sue dozens more for allegedly manufacturing or selling shampoos, soaps and other care products without attaching labels warning consumers that they contained high levels of a carcinogen."

"Secretary of State John Kerry said Monday that a large-scale chemical weapons attack occurred in Syria. There are still many questions about chemical weapons, some of which can be answered easily and some of which can't."

"BENTON HARBOR -- While inspecting a house for lead contamination, Steve Weldert came across a child's toy dump truck in a window sill filled with paint chips."

"Even the best national data on chemical accidents is wrong nine times out of 10."

"A Dallas Morning News analysis of more than 750,000 federal records found pervasive inaccuracies and holes in data on chemical accidents, such as the one in West that killed 15 people and injured more than 300."

"In fact, no one at any level of government knows how often serious chemical accidents occur each year in the United States. And there is no plan in place for federal agencies to gather more accurate information.

"California public health officials suggest limiting hexavalent chromium in drinking water to 10 parts per billion. Environmentalists say that's not nearly strict enough."

"At least three people were killed by an ammonia gas leak from a pipeline owned by state oil monopoly Pemex in southern Mexico on Tuesday and 1,500 people were evacuated from the area and taken to shelters, the company said."