Finnish health authorities warn of legionella risk from bagged soil and compost

The Finnish Institute for Health and Welfare (THL) and the Finnish Food Authority have issued a warning about the risk of legionella bacteria in dry soil and compost products after a record number of infections last year.

In 2023, Finland recorded over 80 cases of legionellosis, a severe form of pneumonia caused by the legionella bacterium. Nearly half of those infected reported exposure to soil or compost products before falling ill, according to THL.

The reason for the increase in soil-related cases remains unknown, the agency stated. Legionella occurs naturally in small amounts in fresh water and soil, and may also be present in commercial soil and compost products.

Authorities advise against inhaling dust from dry soil or compost, as the bacteria can cause serious pneumonia if it reaches the lungs. The risk of illness is highest among the elderly and those with weakened immune systems, though most healthy individuals do not fall ill even if exposed.