Rep. Jim Hansen, R-Utah, is finding out why people who live in glass houses shouldn't throw stones.

His work on the House Ethics Committee essentially makes him one of Congress's designated stone throwers who must suggest punishment for House members who act unethically.Such work also makes him a prime target for allies of those being investigated and for those who figure someone has to watch the watchdogs.

To add fuel to the fire, the ethics committee has been investigating allegations against the most powerful member in the House - Speaker Jim Wright, D-Texas. That creates the potential for some serious stone throwing by all sides.

Not surprisingly, Hansen found himself being attacked at least twice last week because he is one of the people who may be taking aim at Wright.

One indirect attack came from a letter circulated among House Democrats by several of their leaders. They claimed right-wing Republicans were pressuring Hansen and other committee Republicans "to hang him (Wright) regardless of the evidence."

It said a group called the Conservative Campaign Fund (formerly citizens for Reagan) was sending out mailings in his district claiming that Hansen and his fellow Republicans had to vote for censure or expulsion of Wright, or they would be guilty of white-washing his sins. It said House Republican leaders were also pressuring the committee to hang Wright.

Hansen said in an interview that such allegations and inferences that he and other committee members would give in to such pressure even if it existed are "just ridiculous."

The other attack against Hansen was spread in newspapers nationwide by a Jack Anderson column that suggested that once the ethics committee finished investigating Wright, it should start investigating its own members - and named several legal "but sleazy" actions by Hansen.

Included were his use of campaign funds to buy a $22,555 vehicle. Also, it pointed out that Hansen took tens of thousands of dollars in campaign funds and thousands more in speech fees - called honorariums - from defense contractors interested in his work on the House Armed Services Committee.

Hansen said in response that such actions are legal, and hundreds of other Congressmen do the same sorts of things. He is being singled out - he observes correctly, whether or not his motives are totally pure - because he is on the ethics committee.

Hansen said his campaign committee bought a truck because it would be tough enough and big enough to take several people and campaign supplies to remote areas in his vast district - the ninth largest in Congress.

"But the Jack Anderson column made it sound like I was tooling around in a Mercedes," he said. "A lot of other congressmen buy cars with campaign money. But I'm the only one he attacked."

Also, Hansen earned $18,000 in honorariums in 1987 - mostly from defense contractors and others interested in his committee work. But 133 House members and 68 senators earned more. But he again was the one singled out because he sits on the ethics committee.

Not surprisingly, Hansen is tired of such attacks after nine years on the ethics committee. They are one reason he asked recently to get off that committee. He said he has been told that soon after the Wright investigation is complete, his wish will finally be granted.

Then he won't be the one throwing the stones anymore, and won't have to watch quite so much for other stones to fly in his direction.

But it also leaves questions hanging about whether Congress can police itself if ethics committee members have to worry about the glass house falling on them.