The United States has just officially determined that the Syrian government has used chemical weapons against those rebelling against it.
Here are a few useful resources on chemical weapons:
Syria’s chemical weapons – interactive is from The Guardian.
Syria chemical weapons: where have they been used? is from Channel 4 News.
Chemical weapons may draw U.S. into Syria is an Associated Press interactive.
Avoiding Armageddon is a PBS interactive.
Bio and Chemical Threat is a CBS News interactive.
The Boston Globe has a disturbing photo gallery of what appears to be a recent chemical attack on civilians by the Syrian government.
A Weapon Seen as Too Horrible, Even in War is from The New York Times.
Chemical weapons and the scientists who make them is from The Conversation.
The Science of Surviving a Chemical Weapons Attack is from the PBS News Hour.
What chemical weapons does Syria have? is an infographic from The Washington Post.
Chemical Weapons Watchdog Wins Nobel Peace Prize is from The New York Times.