PRAGUE (AP) — A raging flood wave that inundated parts of Prague is now heading north toward Germany, forcing the evacuation of thousands of people and leading to concerns about the safety of chemical plants.

More than 19,000 people have been evacuated from the flooding that has affected half of the Czech Republic, said firefighters spokeswoman Nicole Zaoralova.

Some 3,000 people had to leave their homes in Usti nad Labem on the Elbe river near the German border where the waters were still on the rise today. High waters have already submerged parts of the city as well many other towns along the Elbe, the biggest river in the country.

They are also threatening major chemical factories, including one that released toxic chemicals into the Elbe during the devastating floods of 2002. The plants have been shut down as a precaution and chemicals removed, authorities said.

Czech public television said a barrier that protects one chemical plant in Lovosice was leaking today and it was not immediately clear if it might be completely flooded.