Workers at an Indiana pork plant have reported tingling and numbness in their arms and legs and general fatigue - the same symptoms that affected employees at a plant in Austin, Minn. in December. Federal health officials are investigating the possibility that the illnesses among the workers in the two states are related.

Minnesota health officials said that the Centers for Disease Control and Prevention and the Indiana State Health Department are investigating the new cases. State health officials have declined to say how many Indiana workers have been affected by the mystery neurological ailment, but these are the first cases to occur outside of the initial outbreak in Minnesota. The plant has not been identified.

"There are a couple of cases that are similar," said Ruth Lynfield , Minnesota state epidemiologist.

She said that, like the 12 workers at the Quality Pork Processors plant in Austin, those in Indiana were using a powerful air compression system to remove brains from pig heads. Blood and brain tissue gets sprayed into the air.

Austin workers first reported getting sick in December 2006, around the same time as the processing system was first put into use. Quality Pork Processors has shut it down and provides workers with goggles and face masks.

The investigators at the Minnesota Department of Health and the CDC are looking for similar cases at other processing plants that use the high-pressure air system.