GREENSBURG, Ind. (AP): Production has come to a halt at the Honda assembly plant in Greensburg after an unknown substance was found there.

Honda spokeswoman Anita Sipes confirms the production shutdown after the substance was discovered Thursday morning. She says the plant “is taking every precaution to protect the health and safety'' of its workers.

Sipes says no employees were sent home due to the discovery.

Honda Manufacturing of Indiana President Bob Nelson said the powdery substance was sent with a note to the plant and the substance was being tested.

No injuries have been reported.

The 1.3 million-square-foot plant about 50 miles southeast of Indianapolis opened in October 2008. It assembles two Honda Civic models and one Acura ILX model. It has about 2,000 workers.