concurring and dissenting.
I concur with the majority opinion, except as to the admission of the Reitan letter. In my view, this letter constituted hearsay, and its admission, together with the comments that counsel for respondents were permitted to make about it, were so prejudicial that the judgment should be reversed and the case remanded. The rationale for my conclusion is admirably set forth in part I of the original opinion of Justice Bistline, upon which rehearing was granted. That portion of the original opinion is set forth below.
“I.
“Plaintiffs first contend that the trial court erred in admitting a letter by one Dr. Ralph Reitan because it was hearsay not subject to cross-examination and was extremely prejudicial. We agree.
“The principal reason for the hearsay rule is to exclude evidence which cannot be tested through cross-examination:
The rule against hearsay evidence excludes the statement of a person not under oath and not subject to cross examination when the statement is offered for the purpose of proving the truth of a fact contained in it. [Citations omitted.] ... [I]t would appear that the most objectionable feature of hearsay is the lack of cross examination.
G. Bell, Handbook of Evidence for the Idaho Lawyer 126 (2d ed. 1972).
The heart of Dr. Reitan’s letter is as follows:
I know of no literature, or even clinical experience, relating to possible toxic effects of urea formaldehyde foam. A *164problem in evaluating such possible effects stems from (1) a lack of definitive information concerning their possible effects, coupled with (2) the problem of ruling out the many other adverse influences that have been identified.
Defendant’s Ex. No. 1A (emphasis original).
“Plaintiffs’ expert, psychologist Dr. David Hildebrandt, had written to Dr. Rei-tan regarding the availability of scientific evidence to support a causal link between UFFI and formaldehyde poisoning. A key test used by Dr. Hildebrandt in his neurological evaluation was the Halstead-Reitan Battery of Neuropsychological Tests, developed in part by Dr. Reitan. The letter was an exhibit which the defendants had marked and identified at the taking of Dr. Hildebrandt’s deposition. The letter was offered in evidence at the trial by the defendants while Dr. Baker, a plaintiffs’ witness, was testifying on cross-examination.
“Defendants assert that the letter was introduced to impeach the statement of Dr. Baker that, in formulating an opinion, he had completely reviewed Dr. Hildebrandt’s deposition. Dr. Baker testified that he was not aware of the letter, had not seen it, and hence had not relied upon it. Defendants argued that the letter was not introduced to prove the truth of its contents, and hence was not hearsay. The trial judge was convinced by this argument and admitted the exhibit.
“First of all, accepting that the purpose for the exhibit was impeachment, and accepting that the letter was a part of the deposition, all that was required was to establish that Dr. Baker was in error when he .said that he had reviewed the entire deposition. The contents of the letter were irrelevant to this purpose.1
“Second, the letter was irrelevant to the question of the basis for Dr. Baker’s opinion. Defendants cite Zier v. Shamrock Dairy of Phoenix, Inc. [4 Ariz.App. 382], 420 P.2d 954 (Ariz.App.1967) for the proposition that when cross-examining an opposing expert witness a party is granted a wide range of inquiry into the basis of the expert’s opinion. However, the case is off point because here Dr. Baker said he had not even seen, much less relied on, the letter in forming his own opinion. Even more significantly, Dr. Hildebrandt himself said in his deposition that he did not rely on Dr. Reitan’s letter. Thus, the letter played no part in the opinions of either Dr. Baker or Dr. Hildebrandt. Nevertheless, at the very outset of the trial, defendants’ counsel was given the opportunity to read the letter to the jury and have it placed in evidence. [Emphasis in original.]
“In that manner, the statement of a world renowned specialist were laid before the jury without his being called as a witness and subjected to cross-examination. Admission of the exhibit was classic hearsay, and its admission was a clear abuse of discretion.
“The letter is objectionable for reasons other than its hearsay nature. Its negative probative value is outweighed by its vastly prejudicial effect. Under the current Idaho Rules of Evidence, Rule 403 provides that such evidence may be excluded. Those rules were not in effect at the time of trial, but Rule 403 is consistent with prior Idaho case law. See State v. Abel, 104 Idaho 865, 870, 664 P.2d 772, 777 (1983); Comment to Rule 403, Report of the Idaho State Bar Evidence Committee (1985).
“The content of the letter was in error; contrary to Dr. Reitan’s statement, there was at that time literature relating to the possible toxic effects of UFFI. Some of the articles were attached as exhibits to Dr. Hildebrandt’s first deposition.2 The Reitan letter was extremely prejudicial because Reitan was one of the two developers of the key test for brain damage used by Dr. Hildebrandt to document an important part of the Lundstroms’ injuries. The letter could well have created the impression that *165plaintiffs’ experts possessed no scientific basis supporting the theory of plaintiffs’ case. Defendants’ counsel were not remiss at final argument to the jury in capitalizing on the court’s error:
But there’s absolutely no proof that this chemical is toxic and that it gets to the brain and it would impair someone. Now we hear a lot about the Halstead-Reitan test. And I want you to read Exhibit 3, because that’s the letter from Dr. Reitan himself. Here’s the author of that test we’re all arguing over, and he says, “I know of no literature” — and this is dated January 1st, 1984 — “or even chemical experience relating to possible toxic effects of urea formaldehyde foam. A problem in evaluating such possible effects stems from, one, a lack of definitive information concerning their possible effects, coupled with, two, the problem of ruling out the many other adverse influences that have been identified. Sorry I can’t be of help.”
Now that’s a fact. This is an absolute expert in the field whose test everybody uses, and he just says, no, as of January 1, 1984, there’s no literature or chemical experience relating to possible toxic effects of urea formaldehyde foam insulation. Now that’s a fact. And that’s the letter. I don’t see how, based on a letter such as that, they can come up with a theory that the levels we’re discussing can cause the harm they’re complaining of.
R., Vol. 7, pp. 1867-68 (emphasis added).
“Therefore, the introduction of the Rei-tan letter was error. It was argued to the jury and could not have been other than prejudicial to the plaintiffs, especially when combined with the exclusion of plaintiffs’ scientific articles,.... ”
BISTLINE, J., concurs.. In any event, this impeachment was improper. Whether Dr. Baker had reviewed Dr. Hilde-brandt’s deposition was clearly collateral to the issues at trial.
. Another issue on appeal is the trial court’s rejection of these articles, discussed infra.