From the Daily Telegraph 20 Mar 2010
Recent stories about catching Legionnaires' disease from compost are, thankfully, very rare. Below are a few precautions gardeners can take to stay safe when working in the beds, borders and greenhouse:
Always wear gloves whenever handling soil, compost, fertiliser or pesticides. For fiddly work such as taking cuttings or fine weeding, swap bulky fabric gloves for latex ones or thin, plastic gardening gloves.
Wear gloves and a long-sleeved shirt when pruning plants that can cause skin irritations, for example: ivy, fremontodendron, euphorbia or rue.
Always wash your hands before eating. Keep a hand-sterilising gel down in the potting shed or at the allotment.
Do not open bags of compost or potting media with your nose and mouth right over it, and fold over the top of the bag when finished. Avoid potting up in confined spaces. Moisten dry potting media before use and consider wearing a dust mask.
In very hot weather, especially in greenhouses, it is possible, although rare, for Legionella (Legionnaires' disease) to multiply in warm water to potentially harmful levels. Avoid storing potting media in greenhouses and leaving full hoses in the sun after use. Also, when watering pots, avoid splashing.
Keep water storage containers, such as tanks and butts, clean by emptying and scrubbing out once a year.