Questions and answers about the United Nations report on chemical weapons use in Syria:

Q: What kind of chemical weapon was used?

A: At Ghouta, site of the Aug. 21 attack, the team found evidence of sarin gas on many ground-to-ground rocket fragments. Soil samples in the vicinity of the landing sites were saturated with sarin. Blood and urine samples taken from victims found sarin poisoning and breakdown components of sarin.

Q: How was the gas delivered?

A: The U.N. team found remnants of rockets. The warhead had a capacity to hold about 14.8 gallons of liquid sarin. The rockets were "variants of the M14 artillery rocket, with either an original or improvised warhead." The team was able to trace back the trajectories of two of the rockets and found their path could have come from a single, multi-barreled launcher.

Q: What symptoms did people show?

A: The team examined 36 survivors of the attack, and found loss of consciousness in 78 percent; shortness of breath in 61 percent; blurred vision in 42 percent; eye irritation or inflammation in 22 percent; excessive salivation, or vomiting, in 22 percent; and convulsions or seizures in 19 percent. Of 34 blood samples taken, 91 percent tested positive for sarin exposure at one laboratory, and 85 percent tested positive at another lab.

Q: who fired the weapons?

A: The U.N. team's mandate was strictly limited to evidence-gathering and testing to determine if a banned chemical weapon was used. Syria had requested the dispatch of the U.N. team to investigate a March 19 incident at Khan al-Assal. After protracted negotiations with the United Nations, agreement was finally reached for the team to check that and two other alleged attack sites. But the team was not to assign blame for the attacks.

The U.N. team reported that while it was at the Ghouta attack site in rebel-held territory, “individuals arrived carrying other suspected munitions indicating that such potential evidence is being moved and possibly manipulated.”

Syria has blamed the opposition for the attack.

U.S. Ambassador Samantha Power said after the Security Council meeting that the rockets used “bore none of the hallmarks of improvised weapons.” She said that “The regime possesses sarin, and we have no evidence that the opposition possesses it.” She added that “It defies logic to think that the opposition would have infiltrated the regime areas to fire chemical weapons on opposition areas.”