A Worcestershire man in his 60s is being treated in hospital after contracting Legionnaires' disease.
The man, who has not been named but worked at Polestar Varnicoat in Pinvin, is said to be poorly but stable in the Worcestershire Royal Hospital.
Health officials are investigating a possible link with a case diagnosed in the same area last summer.
A cooling tower at the printing firm has been identified as the potential source of the outbreak and has been shut down while tests are carried out.
Other potential sources of infection are also being investigated.
Steve Jorden, head of environmental services at Wychavon District Council said: "Environmental Health Officers believe they have identified a potential source and are working together with other health professionals as well as the company involved to prevent any further cases."
Dr Tim Davies, director of public health said: "We believe the likely risk of further cases is low."
He said symptoms include a flu-like illness with muscle aches, tiredness, headaches, dry cough and fever.
"If you think you have this infection you should tell your doctor so that the appropriate investigations and treatment can be started.
"The disease is spread through the air from a water source. Breathing in contaminated aerosols from a contaminated water system is the most likely route of transmission.
"Person to person spread of Legionnaires' disease, for example, by coughing and sneezing does not occur."
A helpline has been set up for advice on the disease on 0845 0501720.