Planning authority employees at Hexagon House in Marsa were again subjected to noxious smells and had even to be asked to work from home for a couple of hours.

Investigations by the Malta Environment and Planning Authority indicate the smells came from a new waste oil treatment plant nearby where tests were being carried out by Waste Oils, a company within the Falzon Group.

The incident occurred last week when a number of employees complained about the strong smell and were allowed to go and work from home until the odours subsided, which took about two hours. Some employees worked through without reporting any problems, a Mepa spokesman said.

Hexagon House had to be evacuated last year after foul smells enveloped the building and one female staff member was retained in hospital for observation.

Investigations had revealed Waste Oils was illegally dumping contaminated water in the sewage system, which the company, however, denied.

This time, investigations established that the source of the foul smells was pilot tests carried out by Waste Oils on its new waste oil treatment plant, as well as several improvements being made to their facility as required by their permit, a Mepa spokesman said. Last February, the company was granted a six-month environmental permit to store, collect and separate waste oils.