For the first time in a couple of decades, Hanford has pumped new radioactive wastes into its notorious Tank SY-101.

Tank SY-101 is the former "burping tank" -- the most famous and infamous of Hanford's waste tanks.

The transfer of about 150,000 gallons of wastes into the double-shell tank finished Thursday, according to officials with the Department of Energy and CH2M Hill Hanford Group.

From there, the wastes eventually will be sent to glassification plants being built nearby.

Volatile hydrogen gas in SY-101 used to build up in the tank's wastes and routinely erupt to the surface in "burps." That increased the danger of an explosion or flames from tank vents.

A mixer pump fixed that problem in 1993. But the pump created gas bubbles that caused the crust to grow thicker and increased the danger of a leak.

Ultimately, Hanford officials pumped out roughly half of the wastes and added water to dilute the remaining wastes to stop the troublesome chemical reactions.

Now CH2M Hill has added 150,000 gallons of wastes to SY-101's existing 900,000 gallons of diluted wastes. The wastes are being monitored so past troubles don't resurface and are part of an effort to transfer a vast amount of wastes from the 200 West Area to the 200 East Area by mid-December.