A publication of Work On Waste USA, Inc., 82 Judson, Canton, NY 13617 315-379-9200 June 20, 1991
Truths, Half-Truths, Statistics
and Dr. Kay Jones.
In Waste Not # 147 we published a letter from two mathematicians, with impeccable credentials, criticizing a statistical procedure being used and advocated by Dr. Kay H. Jones of Zephyr Consulting (and formerly with Roy F. Weston, Inc.) for estimating the dioxin emissions from trash incinerators. We print below a letter we received from Dr. Jones and a response from Drs. Healy and Stanshine. Kay Jones is the chairman of the Monmouth County, NJ, Risk Assessment Committee for a proposed Westinghouse 1,700 tpd garbage incinerator for Monmouth (see Waste Not # 132). Please note that Waste Not #147 was incorrect in stating that the risk assessment for this proposal had been performed- it is still in the preparation process.
May 13, 1991, Letter from Kay H. Jones
I see by your Waste Not 147 that you continue to distort the facts to suit your objectives. For example your headline states ...serious error in risk assessment performed by Kay H. Jones.... A total untruth. (1) The risk assessment has yet to be completed. (2) HDR is conducting the risk assessment in accordance with NJDEP guidance. (3) My committee, including Dr.s Healy and Stanshine, are acting in a review capacity.
Enclosed is a copy of the rebuttal memo to their criticisms of the Seibert et al book chapter, which I co-authored. I would hope that you would have the professional courtesy to review my response in light of their comments. I think youll find that their points and concerns are unfounded in fact relative to underestimating risks for the Monmouth Co. facility or any other facility, including those previously permitted in N.J.
Your last sidebar footnote is also misleading. From an emissions testing point of view (and providing you read and understood how the data is presented in the book chapter) the use of the 95% C.I. [confidence interval - Eds.] describes possible variation in the true geometric mean when assuming that the data base represents variation over time at a single facility. This is clearly stated in the text. This variation needs to be considered from a regulatory perspective when you make measurements at the same facility in the future. On the other hand, in a generic risk assessment it is more appropriate to use the 95% quantile value from a multiple facility data set (of like technology). This has always been my philosophy and recommended approach to generic risk assessments.
It would be appreciated if you would print this letter and any portion of the rebuttal as you wish. I doubt that you will do it because it would set a precedent for others to enlighten your readership on the many half truths and untruths contained in your publication series. Professional disagreements are acceptable, unethical conduct is not.
Signed, Kay H. Jones, PhD, Zephyr Consulting, 2600 Fairview Ave. E., Suite 18, Seattle, WA 98102.
June 14, 1991, Response from Drs. Healy and Stanshine
In Waste Not No. 147, you published an article entitled Mathematicians find serious error in risk assessment performed by Kay H. Jones for a WESTINGHOUSE 1,700 tpd incinerator proposed for Monmouth County, NJ. You then went on to quote from a letter dated April 8, 1991, which we sent to Mr. Scott Weiner, Commissioner of the NJDEP (a letter to which we have, so far, gotten no response). Since then, you sent us Dr. Jones response to that article. It includes a cover letter and an attached technical rebuttal. This is our response to the letter and the technical rebuttal. In the first paragraph of his letter, Dr. Jones says
(1) The risk assessment has yet to be completed.
This is correct. Our letter to the NJDEP indicated that there was an error in the risk assessment process, but did not indicate that a final report had been issued.
(2) HDR is conducting the risk assessment in accordance with NJDEP guidance. (3) My committee, including Dr.s Healy and Stanshine, are acting in a review capacity.
Although the above statement is literally true, it does not indicate the active leadership role that Dr. Jones takes in the risk assessment. Dr. Jones is a paid consultant. He has chaired almost all of the
committees meetings. He has made presentations to the committee. In particular, he made a presentation, the subject of our previous letter. His personal involvement goes far beyond what the
quoted statement implies. If the Monmouth County Board of Freeholders wants to hire a consultant to provide an independent review of HDRs assessment, we would be glad to provide the Freeholders with some names. In addition, the phrase review capacity understates the contributions and direction
provided by Dr. Jones and his committee to the risk assessment. Dr. Jones and his committees role is far greater than merely commenting on HDRs risk assessment.
In the third paragraph of his letter, Dr. Jones says
From an emissions testing point of view (and providing you read and understood how the data is presented in the book chapter) the use of the 95% C.I. describes possible variation in the true geometric mean when assuming that the data base represents variation over time at a single
A 95% confidence interval provides useful information on the accuracy of an estimate of a population parameter.
(i) It does not tell whether the correct parameter is being estimated. The geometric mean is the wrong statistic to use to estimate average emissions over time. The average emissions over time should be estimated by the arithmetic mean.
(ii) The data used in the book chapter was not taken at different times from a single facility. As a result, a 95% C.I. based on this data does not tell how much variation to expect over time in measurements taken from a single facility. The measurements were collected from many facilities, but no facility was measured at two different times. There was no basis established for assuming how a single facility would behave over time. We do not understand why Dr. Jones talks about variation over time at a single facility when he has no data which can be used to estimate variation over time.
In the last sentence of his technical attachment, Dr. Jones says
In summary, the major criticisms are for the most part based on a misunderstanding of the objectives of the chapter and how the data might be used in the Monmouth Co. R/A.
In response, we would like to cite another document by Dr. Jones. (See Kay Jones, Connett et al. R/A Paper, memorandum to the (Monmouth County) Ad Hoc Risk Assessment Committee, January 2, 1991, Comment No. 23.) In that document he states,
The emissions factor used in the risk analysis most likely case was the geometric mean....The risk analysis was also performed using the upper 95% value. All Weston risk analyses (which I have directed) employed both values.
Thus, regardless of Dr. Jones objectives, the statistical technique described in the chapter is the one that he always used, at least for as long as he was at Weston, Inc. It is apparently a standard methodology in incinerator risk assessment. Because this approach has been used in risk assessments, there are people living near operating incinerators and proposed incinerator sites who may have excessively optimistic notions of the risk to which they are or will be exposed. They have a right to know what the real risks are. Earlier risk assessments should be re-examined and, if necessary, corrected to take into account statistical errors and allow the public to know their risks.
Signed, Dr. John D. Healy, 100 Laurel Ave, Lincroft, NJ 07738.
Dr. Jerome A. Stanshine, 24 Tudor Drive, Wayside, NJ 07712.
Waste Not Comments: With reference to the last paragraph of Dr. Jones letter. Waste Not does its best to report accurately on the machinations of the waste industry and the consultants who serve it. We can make mistakes -like anyone else- and we do our best to spot them and correct them. We do NOT set out to print half-truths or untruths. We like many other citizens, got into this issue because of the lies and distortions we saw being perpetrated by so-called independent experts promoting the incineration industry.
WASTE NOT # 154 A publication of Work on Waste USA, published 48 times a year. Annual rates are: Groups & Non-Profits $50; Students & Seniors $35; Individual $40; Consultants & For-Profits $125; Canadian $US45; Overseas $65. Editors: Ellen & Paul Connett, 82 Judson Street, Canton, NY 13617. Tel: 315-379-9200. Fax: 315-379-0448.