Thread by @DBrozeLiveFree

Day 4 of 2nd Phase of the #FluorideLawsuit continues for final session.

FAN Michael Connett resumes questioning of witness Dr. Ralph Barone.

Connett: One of the comments NASEM made was to incorporate elements of the NTP's approach for reviewing, correct?

Barone agrees, but...

Connett: is there any example you have of a perfect review?

Barone: the main thing is to provide transparency and objective criteria. That's the point of a systematic review.

Connett has no further questions.

EPA begins cross examination of Dr. Ralph Barone. Asks him his responsibilities as the senior science integrity official. Barone explains.

EPA asks Barone to explain what a "science integrity officer".

EPA asks Barone his education. Barone has a PhD, Masters and Bachelor. Asks Barone when he started working for the EPA. (1990)

Barone says he started out a contract scientist with the EPA, before becoming a government scientist by 1995.

EPA asks Barone to explain the details of a hazard assessment.

EPA is still going through Barone's career within the EPA, asking him to detail each position.

EPA still having Barone go through his work history. They appear to be attempting to establish his credibility.

Barone discusses how he lead the first 10 risk evaluations conducted by the EPA.

EPA: in your 30 year career scientist with the EPA is it fair to say you have always been involved in risk assessment in some way?

Barone confirms.

EPA: let's turn to the first 10 risk assessments conducted by the EPA. Could you explain how the EPA determines risk under TSCA?

Barone: We look at the risk across various factors...

Judge Chen interrupts to ask for clarity.

EPA attorney puts graph on screen relating the Risk Evaluation Process. Dr. Barone is explaining the process from Hazard Assessment, Exposure Assessment, Risk Characterization to Risk Determination.

EPA asks Barone to explain the risk assessment portion of the Risk Evaluation process. (much of this was already discussed with FAN Michael Connett)

EPA: What I want to do know is drill down into each part of the risk evaluation process to make sure we understand...

Now showing "Hazard Assessment" and discussing this 1st step in the 4 step process of Risk Evaluation under EPA's TSCA.

Barone explains you go from Hazard ID, then to "weights of the scientific evidence" & "dose response assessment", and eventually to "Hazard Characterization".

EPA: at the "hazard id" level is the EPA looking at specific doses, high dose vs low dose?

Barone says no, the EPA is looking at all studies in this step.

Barone is now explaining the "Weight of the Scientific Evidence" box (qualitative analysis of the evidence, identifying studies for endpoints to carry forward to dose-response analysis).

EPA: asks Barone to discuss the "Bradford Hill considerations" and whether the EPA (at this stage of Hazard ID) is using a causative approach.

Barone says they are not looking for proof of a causation necessarily.

Judge Chen asks for some more clarity.

EPA: at this stage of the analysis are we looking at exposure ranges?

Barone says no, and explains how this stage of analysis works. "we are looking for the biological range of response and how that relates to exposure".

EPA: how is it that the agency selects a study that it will take forward to dose response analysis?

Barone: we're trying to consider the range of studies that might capture the effects of a toxin.

EPA: you testified earlier that a study cant be considered in a vacuum, what do you mean by that?

Barone: if we have conflicting evidence, we need to be able to explain that... That coherence and consistency are key factors in making decision.

EPA asks Barone to discuss the box on "Dose-Response Assessment" and what is meant by "identifying Points of Departure (POD)".

Barone: arriving at a point of departure for a low quality study is not advisable.

EPA: how does the agency arrive at the POD?

Barone: First thing you have to decide is what the benchmark dose is. Barone goes on to explain the EPA process for determining POD.

EPA: I want to unpack what you said about the testimony of Dr. Grandjean. He said the linear model is the default model, is that true?

Barone: no, he might have been told that but its not true.

EPA attorney and Dr. Barone are getting into the weeds here about "Dose metric" and specific models used by the EPA scientists.

EPA asking Dr. Barone is EPA has used a Physiologically based pharmacokinetic (PBPK) model for the first 10 hazard evaluations.

Barone says yes and shares examples of using PBPK models.

Judge Chen asks some more clarifying questions to Dr. Barone.

Judge Chen and Barone are still going back and forth.

We have about 10 minutes left in this session for today.

EPA: you said in 5 of the evaluations the EPA used PBPK model, what did you do in the other 5?

Barone says the EPA used animal studies to determine a POD.

EPA: has the EPA ever "thrown out" high dose studies vs low does studies?

Barone: we dont throw anything out, we identify the strengths and weaknesses. We are looking for the most robust studies.

Barone is explaining how the EPA looked at risks posed by PCE, and how that compares to other evaluations.

EPA: is the agency able to arrive at a point of departure from a high dose study?

Barone: all the time.

EPA wraps their point on Hazard Assessment and Characterization, and Judge Chen calls it for the end of the day.

#FluorideLawsuit will resume tomorrow morning at 8:30 am Pacific.

I will be going live this afternoon to discuss the 1st week.