"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."

"Anti-government activists in Syria are accusing President Bashar al-Assad's forces of deploying a chemical weapons attack on the suburbs of the capital, Damascus. The government denied the attack, but the allegations have prompted the United Nations to call an emergency meeting. Melissa Block talks to Washington Post reporter Loveday Morris for more."

"Quebec's government last week added rail giant Canadian Pacific Railway Corp. to its list of companies deemed responsible for cleanup costs following last month's deadly oil train derailment."

"U.S. drugmaker Merck & Co said on Friday it is suspending sales of its Zilmax animal feed additive in the United States and Canada following concerns about animals showing signs of distress after use of the product, which is given to cattle to increase their weight before slaughter."

"ROCKAWAY BEACH, Ore. -- From her front porch, Nancy Webster has a clear view of the hills just east of the coast highway, a western hemlock forest that's home to Rockaway Beach's water supply."

"Trains smack of progress, freedom and adventure. It’s said that railroads revolutionized America. The Association of American Railroads (AAR) touts the safety record of the rails: 'In 2012, North American railroads safely delivered more than 2.47 million carloads of hazardous materials.' But sometimes trains leak, derail or just plain explode."

"New research finds that copper in amounts readily found in our drinking water, the foods we eat and the vitamin supplements we take likely plays a key role in initiating and fueling the abnormal protein build-up and brain inflammation that are hallmarks of Alzheimer's disease."

"While the mineral is important to healthy nerve conduction, hormone secretion and the growth of bones and connective tissue, a team of researchers from the University of Rochester Medical Center suggested that too much of it may be a bad thing, and they set about to explore copper's dark side.

"WASHINGTON, DC -- To protect bees and other pollinators, the U.S. Environmental Protection Agency has developed new pesticide labels that prohibit use of some neonicotinoid pesticide products where bees are present. Environmentalists want the agency to take these pesticides off the market."

"A study on the fetuses of pregnant rhesus macaque monkeys has shown that exposure to the chemical bisphenol A, or BPA, led to changes in their lungs that increased the potential for developing asthma."