At least one employee of the planning authority remained in hospital overnight after being exposed to toxic gas even if top officials said all staff had been released after medical check-ups.
After toxic gas prompted an evacuation of Hexagon House, in Marsa, top officials at the Malta Environment and Planning Authority said on Tuesday that all employees had been discharged from hospital after being examined.
However, at least one employee was held overnight in hospital under observation, the Union Ħaddiema Magħqudin said yesterday. The employee has since been dismissed.
On Tuesday, Mepa chairman Austin Walker and a spokesman for the authority denied initial claims by the UĦM that some workers were hospitalised, insisting they were released after further medical checks.
Attempts to contact Mr Walker yesterday proved futile.
Meanwhile, Mepa confirmed that the bad odour that led to the evacuation was hydrogen sulphide gas that had seeped back into the drainage system of the building from the public sewage.
While it ruled out foul play, Mepa said the pungent smell that led to the evacuation was a result of "high levels" of hydrogen sulphide.
It also described the gas as "dangerous".
Hydrogen sulphide is a flammable, colourless gas with a characteristic smell of rotten eggs. Exposure to low concentrations of hydrogen sulphide may cause irritation to the eyes, nose, or throat.
It may also cause difficulty in breathing for some asthmatics.
Brief exposures to high concentrations of the gas can cause loss of consciousness and possibly death.
Works were under way yesterday on the sewage connection located just outside the main gate of Hexagon House and the building's internal sewage system.
According to Mepa a series of inspections by independent experts from Malta Shipyards and the Drainage Department certified that the levels of hydrogen sulphide were below detection limits at the time of the inspections.
The authority said it carried out precautionary engineering works on its drainage system by adding "a number of interceptors to its underground galley". Hexagon House was bought by Mepa from HSBC and the UĦM yesterday questioned the wisdom of the purchase. The union said it had received reports that over a number of years residents and workers in the area had been complaining of the bad smells.
"Even if years have passed, Mepa has not yet solved the problem and this raises doubts on the authority's decision to purchase the place when it had a number of reports in hand on the bad smells," the union said.
ksansone@timesofmalta.com