Chemical warfare. "Scores choke in poison gas attack," from [1] CNN:

BAGHDAD, Iraq (CNN) -- A cloud of deadly toxic gas engulfed an Iraqi town Tuesday, killing six people and leaving dozens of others choking on fumes after a tanker carrying chlorine exploded outside a restaurant.

An Iraqi Interior Ministry officials said the blast in the town of Taji, 12 miles (20 km) north of Baghdad, was caused by a bomb on board the tanker.

There were contrasting figures on the casualty toll. Baghdad security plan spokesman Gen. Qassim Atta told state-run al-Iraqiya TV that five people died in the blast and 148 were poisoned by the gas.