Fayerweather W E, Bender J R, Hadley J G, Eastes W
Owens Corning, Toledo, Ohio 43659, USA.
Regul Toxicol Pharmacol. 1997 Apr;25(2):103-20. doi: 10.1006/rtph.1997.1087.
California Proposition 65 (Prop65) provides a mechanism by which the manufacturer may perform a quantitative risk assessment to be used in determining the need for cancer warning labels. This paper presents a risk assessment under this regulation for professional and do-it-yourself insulation installers. It determines the level of insulation glass fiber exposure (specifically Owens Corning's R-25 PinkPlus with Miraflex) that, assuming a working lifetime exposure, poses no significant cancer risk under Prop65's regulations. "No significant risk" is defined under Prop65 as a lifetime risk of no more than one additional cancer case per 100,000 exposed persons, and nonsignificant exposure is defined as a working lifetime exposure associated with "no significant risk." This determination can be carried out despite the fact that the relevant underlying studies (i.e., chronic inhalation bioassays) of comparable glass wool fibers do not show tumorigenic activity. Nonsignificant exposures are estimated from (1) the most recent RCC chronic inhalation bioassay of nondurable fiberglass in rats; (2) intraperitoneal fiberglass injection studies in rats; (3) a distributional, decision analysis approach applied to four chronic inhalation rat bioassays of conventional fiberglass; (4) an extrapolation from the RCC chronic rat inhalation bioassay of durable refractory ceramic fibers; and (5) an extrapolation from the IOM chronic rat inhalation bioassay of durable E glass microfibers. When the EPA linear nonthreshold model is used, central estimates of nonsignificant exposure range from 0.36 fibers/cc (for the RCC chronic inhalation bioassay of fiberglass) through 21 fibers/cc (for the i.p. fiberglass injection studies). Lower 95% confidence bounds on these estimates vary from 0.17 fibers/cc through 13 fibers/cc. Estimates derived from the distributional approach or from applying the EPA linear nonthreshold model to chronic bioassays of durable fibers such as refractory ceramic fiber or E glass microfibers are intermediate to the other approaches. Estimates based on the Weibull 1.5-hit nonthreshold and 2-hit threshold models exceed by at least a factor of 10 the corresponding EPA linear nonthreshold estimates. The lowest nonsignificant exposures derived in this assessment are at least a factor of two higher than field exposures measured for professionals installing the R-25 fiberglass insulation product and are orders of magnitude higher than the estimated lifetime exposures for do-it-yourselfers.
加利福尼亚州第65号提案（Prop65）提供了一种机制，制造商可通过该机制进行定量风险评估，以确定是否需要贴上癌症警示标签。本文针对专业和自己动手安装绝缘材料的人员，根据该法规进行了风险评估。它确定了绝缘玻璃纤维的暴露水平（具体为欧文斯科宁公司的R - 25 PinkPlus与Miraflex），假设终生暴露，在Prop65法规下不会构成重大癌症风险。Prop65将“无重大风险”定义为每10万名暴露者中新增癌症病例不超过1例的终生风险，非重大暴露定义为与“无重大风险”相关的终生工作暴露。尽管类似玻璃棉纤维的相关基础研究（即慢性吸入生物测定）未显示致癌活性，但仍可进行此判定。非重大暴露是根据以下方法估计的：（1）大鼠中最新的RCC非耐用玻璃纤维慢性吸入生物测定；（2）大鼠腹腔内注射玻璃纤维的研究；（3）应用于传统玻璃纤维的四项慢性吸入大鼠生物测定的分布决策分析方法；（4）从耐用耐火陶瓷纤维的RCC慢性大鼠吸入生物测定进行外推；（5）从耐用E玻璃微纤维的IOM慢性大鼠吸入生物测定进行外推。当使用美国环境保护局（EPA）的线性无阈值模型时，非重大暴露的中心估计值范围从0.36纤维/立方厘米（对于玻璃纤维的RCC慢性吸入生物测定）到21纤维/立方厘米（对于腹腔内注射玻璃纤维的研究）。这些估计值的95%置信下限从0.17纤维/立方厘米到13纤维/立方厘米不等。从分布方法或对耐用纤维（如耐火陶瓷纤维或E玻璃微纤维）的慢性生物测定应用EPA线性无阈值模型得出的估计值介于其他方法之间。基于威布尔1.5击无阈值模型和2击阈值模型的估计值比相应的EPA线性无阈值估计值至少高出10倍。此次评估得出的最低非重大暴露比安装R - 25玻璃纤维绝缘产品的专业人员的现场暴露至少高出两倍，并且比自己动手安装者的估计终生暴露高出几个数量级。
