Owens Corning scientists admit cancer danger?

In a stunning announcement reported by the United Auto Workers union, four Owens Corning scientists, in a paper published in the journal Inhalation Toxicology, recommended an average occupational exposure limit for an 8-hour day of .05 fibers per cubic centimeter of air, or about half a fiber per cubic meter of air.  This is considerably lower than the current U.S. standard for asbestos (1 fiber per cubic meter) or the long-standing-but-not-enforceable NIOSH recommendation of 3 fibers per cubic meter for fiberous glass dust.  It is much more restrictive than the "nuisance dust" standard, which is the law in the United States, and is measured in terms of weight instead of fiber counts.The scientists say the lower exposure standard is needed to bring the cancer risk down to 1 in 100,000 workers.

Read the story from the UAW.

The UAW echoed a point we have been making for years... if the fibers do dissolve in a few days or weeks or months, as the industry insists, what do those fibers break down into, and how dangerous are those by-products?

Stay tuned for more details.

Here is the abstract for the article:

QUANTITATIVE RISK ASSESSMENT OF DURABLE GLASS FIBERS

William E. Fayerweather ^A1, Walter Eastes ^A2, Francesco Cereghini ^A3, John G. Hadley ^A4

^A1 Owens Corning World Headquarters, Toledo, Ohio, USA
^A2 Owens Corning World Headquarters, Toledo, Ohio, USA
^A3 Owens Corning World Headquarters, Toledo, Ohio, USA
^A4 Owens Corning World Headquarters, Toledo, Ohio, USA

Abstract:

This article presents a quantitative risk assessment for the theoretical lifetime cancer risk from the manufacture and use of relatively durable synthetic glass fibers. More specifically, we estimate levels of exposure to respirable fibers or fiberlike structures of E-glass and C-glass that, assuming a working lifetime exposure, pose a theoretical lifetime cancer risk of not more than 1 per 100,000. For comparability with other risk assessments we define these levels as non-significant exposures. Nonsignificant exposure levels are estimated from (a) the Institute of Occupational Medicine (IOM) chronic rat inhalation bioassay of durable E-glass microfibers, and (b) the Research Consulting Company (RCC) chronic inhalation bioassay of durable refractory ceramic fibers (RCF). Best estimates of nonsignificant E-glass exposure exceed 0.05-0.13 fibers (or shards) per cubic centimeter (cm³) when calculated from the multistage nonthreshold model. Best estimates of nonsignificant C-glass exposure exceed 0.27-0.6 fibers/cm³. Estimates of nonsignificant exposure increase markedly for E- and C-glass when non-linear models are applied and rapidly exceed 1 fiber/cm³. Controlling durable fiber exposures to an 8-h time-weighted average of 0.05 fibers/cm³ will assure that the additional theoretical lifetime risk from working lifetime exposures to these durable fibers or shards is kept below the 1 per 100,000 level. Measured airborne exposures to respirable, durable glass fibers (or shards) in glass fiber manufacturing and fabrication operations were compared with the nonsignificant exposure estimates described. Sampling results for B-sized respirable E-glass fibers at facilities that manufacture or fabricate small-diameter continuous-filament products, from those that manufacture respirable E-glass shards from PERG (process to efficiently recycle glass), from milled fiber operations, and from respirable C-glass shards from Flakeglass operations indicate very low median exposures of 0, 0.0002, 0.007, 0.008, and 0.0025 fibers (or shards)/cm³, respectively using the NIOSH 7400 Method ("B" rules). Durable glass fiber exposures for various applications must be well characterized to ensure that they are kept below non-significant levels (e.g., 0.05 fibers/cm³) as defined in this risk assessment