PORTLAND, ORE. -- The Gould Battery Dump occupies one of southwest Portland's filthiest warehouse and storage districts, a realm of oil tanks and mud holes and backhoes and barbed wire fences. But to Democratic senatorial candidate Harry Lonsdale, the dump is a gold mine, a resource adding to his rising hopes of defeating Oregon's political colossus, Sen. Mark O. Hatfield (R).

Lonsdale, a chemist and entrepreneur from Bend, has had two news conferences this month outside the Gould dump that filled television screens with pictures of toxic waste. The images were designed to create the impression of Hatfield as a Washington deal-maker who has taken money from chemical companies and not forced them to clean up their mess.

Hatfield, who seemed unbeatable in his quest for a fifth term just a month ago, ignored the attack as the desperate act of a certain loser until a poll published in the Portland Oregonian showed that his August lead of 63 to 27 percent had shrunk to 49 to 43 percent in late September.

"It was a wake-up call," said Hatfield spokesman Bill Calder. Hatfield has counterattacked on television, and much of what is going on in this newly wide-open race is now no prettier than the environs of the Gould dump.

Last week Democrats charged that the GOP telephone bank operation was smearing opponents with loaded questions. Lonsdale spokesman Dan Walter said this included a suggestion that the Democrat planned to "lock up the forests and throw thousands of people out of work." Hatfield staff members publicized the charges of former employees of Lonsdale's company, Bend Research Inc., who said the anti-toxics candidate had been dumping dangerous chemicals at his company's site in Bend.

Gay-rights activists supporting Lonsdale continued to rail against Hatfield's resistance to a state law banning discrimination against gay men and lesbians. And there has been periodical publicity about the travel expenses and savings and loan ties of longtime Hatfield administrative assistant Gerald W. Frank.

The unexpected threat to Hatfield, considered an Oregon political icon after eight years as governor and 24 years in the Senate, has eclipsed the even closer race for governor between Secretary of State Barbara Roberts (D) and Attorney General Dave Frohnmayer (R). In the Oregonian poll, Frohnmayer led 45 to 38 percent in August but dropped to a 44 to 43 percent dead heat in late September.

The governor's race has been spirited, with Frohnmayer labeling Roberts a tax-and-spend liberal in aggressive television commercials, then deciding to fire his advertising agency when editorial writers called him too negative.

Still, the contest lacks the bitter edge of the Hatfield-Lonsdale clash, which involves the political survival of a senator who has long embodied the Oregon tradition of ideological eccentricity. Oregon-based novelist Ursula K. LeGuin once suggested that this state's senators had a mandate to "make the other senators crazy," and Hatfield has had his moments. He is antiabortion, in sharp contrast to Oregon's other Republican senator, the hardline abortion-rights advocate Bob Packwood. In foreign affairs, he is also an unapologetic dove who embraces congressional controls on presidential war-making even when faced with an enemy as unpopular as Iraq's Saddam Hussein.

Looking for a soft spot, Lonsdale has focused on the Gould dump, a threat to the nearby Willamette River and one of seven designated toxic waste sites statewide that have yet to be cleaned up. "The politicians are listening more to their polluting contributors than to the people whose lives and livelihoods are threatened," he said.

In the midst of a raging controversy over plans to limit logging to protect the northern spotted owl, Lonsdale has leaned toward the environmentalists and demanded limits on the export of raw logs which, he said, hinders the creation of "new jobs manufacturing wood products here in Oregon." The assumption is that his stand will please a new generation of nature-loving suburbanites who outnumber lumber mill workers and others enraged by any government intrusion into the timber industry.

In a long piece for the Oregonian, Hatfield called Lonsdale's approach blatantly shortsighted, and could not resist a reference to his foreign policy concerns: "The truth of the matter is that those who would have us lock up all our forests tomorrow are no more interested in addressing the real and difficult questions about Oregon's economic future than my colleagues in Congress are in taking responsibility for the lives of American soldiers in the sands of Saudi Arabia."

Part of Hatfield's strength -- which he hopes will pull him through this unexpectedly tough reelection contest -- has been his attention to staying in contact with constituents. He remembers the names of shopkeepers in tiny rural towns and has come home from Washington at least twice a month despite the grueling coast-to-coast trip.

But time tarnishes even the most carefully tended reputation. Lola Amundson, a tailor in Klamath Falls, recalled Hatfield's controversial dealings with oil pipeline entrepreneur Basil Tsakos six years ago, saying, "He just looks out for himself and his buddies rather than for the rest of us."

"We've had enough of him," said Jim Liston, a rancher living outside Klamath Falls. But Liston stopped short of declaring for Lonsdale. "I just don't know enough about Lonsdale," he said. "I don't know if he would be a good replacement."