July 1, 2014

U.S. Enviro nmental Protection Agency

Office of Pollution Prevention and Toxics

Confidential Business Information Center (CBIC) – TS7407M Attention: Audrey Binder EPA East Building, Room 6428

1201 Constitution Avenue, NW Washington, DC 20004-3302

Dear Ms. Binder:

Reference: PMN P-12-0425 Submission Report Number –

Interim Results of 28-Day Subacute Inhalation Toxicity Study

As disclosed in our letter to the Agency dated 16 August 2013, a 28-Day Subacute Inhalation Toxicity Study was scheduled for the PMN substance. The objective of this inhalation study was to evaluate the potential subchronic toxicity of the test substance when administered 6 hours per day, 5 days per week by inhalation to male and female rats for a period of a pproximately 28 days. This letter is to inform you of the interim results of this study with the PMN substance ( PMN P-12-0425 ).

Under the conditions of this study, the no-observe d-adverse-effect-concentration (NOAEC) for in male rats was 2500 ppm based upon test substanc e-related diuresis-induced dehydration associated with increased serum total protein, albumin and globulins as well as a single incidence of degeneration/atrophy of ameloblastic epithelium ob served in males exposed to 5100 ppm. The NOAEC for female rats was 5100 ppm, the highest exposure concentration tested in this study. The estimated completion date for this final report is July 2014.

The objective of this study was to assess the potential su bchronic toxicity of in rats. Four groups

of 20 male and 20 female Crl:CD(SD) rats each we re exposed whole body, 6 hours per day, 5 days per week to 0.00 ± 0.00 (air-exposed control), 1000 ± 4.8, 2500 ± 14 or 5100 ± 25 ppm (mean ± S.E.M) over a 4-week period for a total of 21 exposures. Animals were weighed, observed for clincial signs of toxicity and had body weight and food consumption evaluations throughout the study. Animals were subject to an ophthalmology exam and neurobehavioral evaluation prior to initiation of exposures and during the 4 th week of exposure. Following 4-weeks of exposure to groups of 10 male and 10 female rats from each exposure level were fasted, blood and urine samples collected for clinical pathology and sacrificed one day following their final exposure for anatomical pathology evaluation including microscopic tissue evaluation. Following a 14-day recovery period, groups of 10 male and 10 female rats were fasted, blood and urine samples collected for clinical pathology and were sacrificed for anatomical pathology evaluation including microscopic tissue evaluation.Page 2 of 3 Male rats exposed to 5100 ppm demonstrated a statistically significant reduction (5.7%) in body weight one day following their final exposure when compared to the air exposed control group. There was no test substance-related adverse effects on body weight gain, food consumption, clincial signs of toxicity or in the ophthalmology exams in male or females at any exposure level to . There was also no test substance-related effects on any neurobehaviora l parameter evaluated in male or females at any exposure level. did not ha ve an effect in the micronucleus assay in any animals exposed during this study as assessed by the number of micronucleated polychromatic erythrocytes.

Consistent with exposure to a fluorinated compound , plasma fluoride was increased in the 2500 and 5100 ppm male and female groups, and urine fluoride was increased in all male and female exposure groups. Following the 14-day recovery period , plasma fluoride concentration was the same as controls in all male and female exposure groups. Urine fluoride levels had not returned to control levels following the 14-day recovery but were decreased to 48, 24, and 15% of th eir previous (end-of-exposure) values in the 1000, 2500, and 5100 ppm male groups, respectively. In re covery group females, urine fluoride levels were

decreased to 42, 23, and 10% of the end-of-exposure values, respectively.

Exposure of male rats to 5100 ppm was associated with increased urine volume and decreased urine specific gravity consistent with diuresis, increased se rum proteins (albumin, globulin and total proteins), and decreased body weight. Increases in serum proteins occurring in association with decrements in body weight in the 5100 ppm male group were considered to be indicative of an adverse, albeit minimal, effect on hydration status (dehydration), li kely occurring secondary to fluoride diuresis. Although evidence of diuresis was also present in males at 1000 and 2500 ppm and in females at 2500 and 5100 ppm, and minimal increases in serum proteins were present in the 1000 and 2500 ppm male groups, these changes were not associated with effects on body weight pa rameters, indicating that hydration status was not significantly altered at these exposure concentrations. Therefore, these changes were likely test substance-related but were considered to be non-adverse. Changes in urinalysis and serum protein

parameters were revers ible following the two-week recovery peri od. There were no changes in clinical pathology parameters considered to be adverse in ma les at 1000 and 2500 ppm or in females at any of the exposure concentrations tested.

Liver hepatocellular hypertrophy occu rred in both sexes at 5100 ppm and in males at 1000 and 2500 ppm at the terminal necropsy and in males at 5100 ppm at the recovery necropsy. This is considered an adaptive response associated with metabolism of xenobiotics and non-adverse. Hyperplasia/squamous metaplasia of the larynx occurred in all exposure gr oups at the terminal necropsy and at 1000 and 5100 ppm in males at the recovery necropsy and in a sing le female at 5100 ppm at the recovery necropsy. Goblet cell hypertrophy/hyperplasia occurred in all ex posure groups at both the terminal and recovery necropsy. These laryngeal and nasal changes are consider ed an adaptive response to irritation and in the absence of severe changes, as occurred in this study, are not considered adverse. Microscopic evidence of fluoride exposure was noted in the inciso r teeth of males at 2500 and 5100 ppm with degeneration/atrophy of ameloblastic epithelium note d in a single 5100 ppm male which was considered adverse. Other findings associated with the fluoride exposure included very slight lamination of dentin at 5100 and 2500 ppm (a single male affected at 2500 ppm), and incomplete decalcification of enamel/dentin at 2500 and 5100 ppm. These latter changes were not considered adverse as the lamination was very minimal and the incomplete decalc ification, while indicative of exposure, is not an adverse finding in the animal.

Once again, under the conditions of this study, th e NOAEC in male rats was 2500 ppm based upon test substance-related diuresis-induced dehydration associated with increased serum total protein, albumin and globulins as well as a single in cidence of degeneration/atrophy of am eloblastic epithelium observed in males exposed to 5100 ppm. The NOAEC for female rats was 5100 ppm, the highest exposure concentration tested in this study.Page 3 of 3 Please contact me if you have any questions about this submission or need further clarification.

Via eTSCA Client cc: Rebecca von dem Hagen (EPA, Office of Air an d Radiation, Stratospheric Protection Division)