The Palaio Faliro Municipality ordered staff to go home on Tuesday amid concerns that the odor constituted a health hazard. [InTime News]

Authorities were still unable late Tuesday to determine the source of a strong odor that spread across Athens’ southern suburbs for hours, alarming residents and triggering widespread speculation about possible chemical leaks.

The lack of official information fueled theories about the cause and composition of the smell, with attention turning to natural gas networks, the Revithoussa LNG terminal, refineries, commercial ships, fuel and liquefied gas storage facilities, and sewage treatment installations at Psyttaleia.

People familiar with chemical compounds said the odor resembled liquefied gas or a petroleum byproduct more than natural gas.

Mass calls from residents to the fire service, DESFA, and gas distribution operator Enaon EDA prompted emergency checks and coordination with the Environment and Energy, and the Civil Protection ministries.