Hanford has removed 18 radioactive waste tanks from its watch list for potentially flammable organic chemicals, the Department of Energy announced Thursday.

That leaves 28 tanks at central Hanford's tank farms that still require extra scrutiny and controls. Eight of the tanks removed from the organics list remain among that group, however, because they have other problems.

Several oversight groups - plus the staff of U.S. Sen. Ron Wyden, D-Ore., agree with DOE's decision to take those tanks off the so-called Wyden watch list, according to DOE.

In 1990, Wyden - then a congressman - wrote legislation that required Hanford to identify tanks that had the potential to release flames or dangerous gases.

Extra safety measures were required for tanks on that "watch list"while studies began to determine how dangerous they were. Ultimately, 54 tanks ended up on that list for one or more reasons.

The four identified problem areas in the tanks were the potential for flammable gases, the potential for flammable organic chemicals, the presence of potentially explosive ferrocyanide gas, and wastes that spontaneously heat up.

After studies indicated in 1996 that the ferrocyanide threat was less than feared, 18 tanks were removed from the list. Some tanks were removed for other reasons.

The remaining 28 tanks on the watch list include:

25 because they could contain potentially flammable levels of gas. The regulatory deadline to finishing dealing with those tanks is September 2001.

Two organic solvent tanks. Hanford officials hope to begin getting those off the list in early 1999.

Tank C-106, which heats up spontaneously. The wastes in the tank are soon to be pumped into a tank better designed to keep those wastes from heating.