TO: Linde Work Group 

Genevieve Roessler, Chair 

FROM: Stephen Ostrow, SC&A 

SUBJECT: Summary of SC&A White Paper Evaluating Various Documents Related to Linde 

Ceramics Plant Special Exposure Cohort (SEC) Petition 00107 and the Site 

Profile 

DATE: April 9, 2010 

INTRODUCTION 

As part of its support for the Advisory Board on Radiation and Worker Health Linde Work 

Group (Linde WG), SC&A reviewed several documents, primarily employee interviews and 

statements, provided by an advisor to the Linde claimants in three different transmittals. As 

directed by the Linde WG, SC&A examined the documents to identify potential implications to 

NIOSH’s Linde SEC-00107 evaluation or site profile that were not already addressed elsewhere, 

and reported its assessment in a white paper, dated March 29, 2010. This summary highlights 

the issues identified in the white paper in a form suitable for the general reader; SC&A noted two 

issues, both of which are currently being addressed by NIOSH. 

WHITE PAPER SUMMARY

SC&A examined the documents to determine if they raised any material issues that have not 

already been addressed or resolved by NIOSH, SC&A, or the Linde WG. “Material issues” is 

interpreted to mean issues potentially affecting dose reconstructions relying on the site profile or 

related to NIOSH’s assertions regarding whether it can reconstruct doses with respect to SEC 

Petition 00107. Much of the contents of the documents relates to either general site history or 

conditions, or to specific worker histories (e.g., testimonies appealing compensation 

determinations), which are not considered material in this report. In addition, much of the 

information is repeated in multiple documents. 

SC&A identified two issues meeting its criteria of unresolved and material—exposure to workers 

in tunnels under Linde buildings and exposure to welders using thoriated tungsten welding rods. 

Tunnels 

Worker statements noted that a system of utility tunnels ran beneath various buildings of the 

Linde facility; the tunnels flooded when it rained or snowed, and contaminants would wash 

down into them. These tunnels are not mentioned, however, in the site profile or in the SEC 

review. SC&A believes that exposures to workers in the tunnels should be estimated. Although 

the issue has not been fully addressed, it was noted by the Linde WG during the January 25, 

2010, teleconference on SEC Petition 00107. During that teleconference, NIOSH committed to 

developing a methodology for estimating doses, and SC&A was tasked by the WG to review 

Summary of Draft Linde Document Review 1 SC&A – April 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 
Summary of Draft Linde Document Review 2 SC&A – April 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

NIOSH’s product when it is available. Hence, although this item is not yet resolved, the 

resolution process is underway. 

Thoriated Tungsten Welding Rods 

Worker testimony called attention to the practice of performing thoriated TIG (tungsten inert 

gas) welding, during which the welder would grind the thoriated welding rod to cut it and to 

shape a point at the end. The process produced airborne dust, and there was no dust collection 

system or respiratory protection provided. SC&A looked at the literature to determine whether 

there could be a potentially adverse radiological health effect from inhaling and ingesting the 

slightly radioactive thoriated tungsten dust. 

TIG welding is commonly used in the welding industry, as the addition of a few percent (1%–

4%) of thorium to the tungsten greatly improves the welding process in several important ways. 

Expert assessments from welding industry organizations, researchers, and the U.S. Nuclear 

Regulatory Commission note that potential external exposures from tungsten electrode dust 

containing some radioactive thorium is minimal, but caution should be taken to minimize 

potential exposures from inhaling or ingesting airborne dust. Possible protective measures 

include proper dust collection, ventilation, and respiratory protection, particularly during 

electrode grinding operations. 

Based on SC&A’s brief review of the thoriated tungsten electrode issue, it believes that, even 

though the literature indicates that the dose to welders may not be significant, NIOSH should 

address the matter in a formal manner. Following an inquiry by SC&A during preparation of the 

white paper, NIOSH indicated that it was in the process of examining the issue on a complexwide basis. Hence, while SC&A finds the issue material, it is currently in the resolution process, 

and SC&A will review NIOSH’s approach when it is available.