Work on a massive and dangerous demolition project at Hanford remains on hold Tuesday after radioactive contamination was found to have spread outside the project area, onto a parking lot.

The KING 5 Investigators have found that out of 100 cars surveyed, eight had plutonium particles on them – four personal cars and four government vehicles. Two of the personal cars with contamination were driven home by the unknowing employees over the weekend.

KING 5 has learned those two employees have agreed to have their homes checked for contamination.

Many workers are taking tests to see if they have inhaled or ingested radioactive isotopes.

This is the latest set back at the demolition of the plutonium finishing plant complex at Hanford, where plutonium buttons for nuclear warheads were produced throughout the Cold War.

In June, a spread of contamination caused 31 workers to be internally contaminated with plutonium particles. Plutonium is known to cause cancer and can stay in the system for years.

Related: Hanford employees told to stay inside as more contamination found

Related: Department of Energy announcement to Hanford employees

DOE Update on Plutonium Finishing Plant by KING 5 News on Scribd