DATE: July 7, 2004 MEMORANDUMSUBJECT Phenol Report of the Antimicrobials Division Toxicology Endpoint Selection Committee.

FROM: Timothy F. McMahon, Ph. D. Chair, ADTC Antimicrobials Division ( 7510C)

THROUGH: John Redden, Roger Gardner, Stephen Dapson, Ph. D., Karen Hamernik, Ph. D., Melba Morrow, D. V. M., Sanyvette Williams Foy, D. V. M, Jonathan Chen, Ph. D., Timothy Leighton, Michelle Centra, Najm Shamim, Ph. D.

PC Codes: 068603 On March 9, 2004, the Antimicrobials Division Toxicology Endpoint Selection Committee ( ADTC) reviewed the available Toxicology data for Phenol and discussed endpoint selection for use as appropriate in occupational/ residential exposure risk assessments. The potential for increased susceptibility of infants and children from exposure to phenol was also evaluated by the committee in order to meet the statutory requirements of the Food Quality Protection Act ( FQPA) of 1996. The conclusions drawn at this meeting are presented in this report. 2 Committee Members in Attendance Members present were: Timothy F. McMahon, Ph. D. Stephen Dapson, Ph. D.; Jonathan Chen, Ph. D.; Timothy Leighton; John Redden; Karen Hamernik, Ph. D., Michelle Centra, Roger Gardner, Ph. D., . Sanyvette Williams, D. V. M.; Melba Morrow, D. V. M., Najm Shamim, Ph. D.

Others present: Samantha Jones ( Versar), Matthew Martin ( Versar), Eric Brown ( Versar), Kathryn Boyle ( RD).

Data Evaluation / Report Presentation Timothy F. McMahon, Ph. D.

Senior Toxicologist 3 COMMITTEE MEMBERS IN ATTENDANCE ( Signature indicates concurrence unless otherwise stated)

Stephen Dapson Jonathan Chen Roger Gardner Karen Hamernik Tim McMahon ( chair)

Melba Morrow John Redden Sanyvette Williams Foy Najm Shamim Michelle Centra Tim Leighton 4 INTRODUCTION Phenol is an antimicrobial pesticide active ingredient used as a sanitizer, bacteriostat, fungicide/ fungistat, tuberculocide, disinfectant, and virucide for a number of use sites, including indoor food uses ( eating establishments equipment and utensils), indoor residential sites ( bathroom premises, hard surfaces, diaper pails, indoor premises, dogs, air ducts), indoor non food ( institutional/ industrial floors, industrial premises/ equipment, laundry equipment, paints) indoor medical ( hospitals), and aquatic non food residential ( swimming pool surfaces)

FORMULA: C6H6O Physical Properties:

Active ingredient: Phenol Color: colorless to light link Physical state: crystalline solid Specific gravity: 1.07 at 20 oC pH: mildly acidic Vapor Pressure: 0.341 mmHg at 25 oC; 2.48 mmHg at 50 oC 41.3 mmHG at 100 oC Solubility: 67 g/ L at 16 oC Molecular mass: 94.11 Melting point: 43.0 oC Boiling point: 181.8 oC at 760 mmHG FQPA HAZARD CONSIDERATIONS 1. Adequacy of the Toxicity Data Base The ADTC concluded that the available toxicity database for phenol was adequate for hazard characterization for the registered uses. In addition to several reports from the scientific literature, there is a recent ( 2002) updated Toxicological Profile in the IRIS database for phenol. 5 2. Evidence of Neurotoxicity The ADTC committee noted neurotoxic signs from acute dermal toxicity studies ( Brown et al.  convulsions; OTS 0515567/ 86 870001405 tremors; Conning DM stimulation of motor nerve endings or spinal motor centers) and from a 15 day inhalation study  tilting plane results showed an effect in treated rats). There were no neurotoxic signs noted from the oral studies using gavage or drinking water as the method of phenol administration. As noted in the IRIS Toxicological profile, " A number of nervous system effects have been observed following phenol dosing. Tremors were observed in one animal that later died ( apparently of dehydration) following dosing via the drinking water ( ClinTrials BioResearch, 1998). Tremors have also been observed in several gavage studies in rats and mice ( NTP, 1983a; Dow Chemical Co., 1994; Moser et al., 1995). However, in a specialized 13 week neurotoxicity study in male and female rats that included an FOB and a detailed neurohistopathology evaluation ( ClinTrials BioResearch, 1998), the only observed nervous system effects were tremors in one animal and decreased motor activity in females. A short term gavage screening study ( Moser et al., 1995) found that the only effect in an FOB was a marginal decrease in motor activity and increased rearing post exposure." This effect could be attributed to the dehydration observed in the study, however, it was also concluded that phenol contributed to the decreased motor activity.

3. Developmental Toxicity Study Conclusions The toxicity profile for phenol presented several developmental and reproductive toxicity studies found in the open literature. These studies are also referred to in the IRIS update as well. In addition, the National Toxicology Program conducted developmental toxicity studies in both rats and mice. The ADTC considered the NTP studies as well as the published report by Ryan et al. ( 2001) to be acceptable for regulatory purposes. Published reports by Kavlock ( 1990) and Bishop ( 1997) were considered unacceptable for purposes of determining the developmental toxicity of phenol, based on study design.

In the NTP rat developmental toxicity study, phenol, in distilled water, was administered to groups of 23 rats/ dose by gavage at dose levels of 0, 30, 60, or 120 mg/ kg/ day from gestation days ( GD) 6 to 15. No significant maternal toxicity was observed up to the high dose of 120 mg/ kg/ day tested in this study. In offspring, the only effect noted was a significant decrease in mean fetal body weight, but no teratogenic effects were observed. Therefore, the maternal toxicity LOAEL is greater than 120 mg/ kg/ day in this study, and the Developmental toxicity LOAEL is 120 mg/ kg/ day.

In the NTP mouse developmental toxicity study, phenol was administered in distilled water to groups of 31 36 mice/ dose by gavage at dose levels of 0, 70, 140, or 280 mg/ kg/ day from gestation days ( GD) 6 to 15. Clinical signs of toxicity were observed in maternal animals at a dose of 280 mg/ kg/ day, which included signs of neurotoxicity ( tremors, ataxia, lethargy). In addition, maternal body weight was decreased during the treatment period ( 31% decrease) and entire gestation period ( 28% decrease). In offspring at the 280 mg/ kg/ day dose, an increase in cleft palate was observed in 8 of 214 fetuses ( 3 litters), although this increase was not statistically significant. The fetuses exhibited reduced mean fetal weights ( male and female combined) and the researchers concluded that the high dose ( 280 mg/ kg/ day) 6 was fetotoxic due to significant reductions ( 18%) in mean fetal weight in treated animals when compared to control. The Maternal and Developmental toxicity NOAEL was 140 mg/ kg/ day, and the Maternal and Developmental toxicity LOAEL was 280 mg/ kg/ day in this study.

In a non  guideline developmental toxicity study ( Narotsky, M. G. and R. J. Kavlock, Journal of Toxicology and Environmental Health 45: 145 171, [ 1995]), phenol was studied for effects on postnatal growth and viability of prenatally exposed rodents as a means to assess the developmental toxicity of phenol ( 99+% purity). Phenol was administered to groups of 17 Fischer 344 rats/ dose at concentrations of 40 or 53.3 mg/ kg/ day once daily from gestation days ( GD) 6 19 for a total exposure period of 14 days. Dams were observed throughout pregnancy. Following delivery litters were examined postnatally and after final examination, dams were sacrificed and uterine implantation sites were counted. Pups, 14 live litters/ dose, were maintained for 21 days.

There were no treatment related effects in mortality ( 100 % survival) of rats receiving phenol for 14 days. Clinical signs of toxicity following administration of phenol were observed and included altered respiration ( e. g., rales and dyspnea) at both dose levels. Maternal weight loss was similar to control levels after two treatments but significantly reduced weight gains were observed after 4 and 10 treatments between GD 6 20. Maternal body weight gain was reduced 21 and 24% from controls in animals treated with 40.0 and 53.3 mg/ kg/ day phenol, respectively. The Maternal Toxicity NOAEL is less than 40 mg/ kg/ day ( lowest dose tested). The Maternal Toxicity LOAEL is 40 mg/ kg/ day, based on reduced body weight, body weight gain, and respiratory distress ( rales and dyspnea).

One low dose and two high dose animals experienced full resorption resulting in significantly reduced litter sizes and a marginally significant increase in prenatal loss in the high dose group. The three dams with resorbed litters had severe respiratory signs and an additional high dose female also had severe respiratory signs with excessive perinatal mortality in its litter. The high dose dam had markedly reduced pup weights on postnatal day ( PND) 1 resulting in a marginally significant reduction for the group. Kinked tails were observed in 2 of the 4 survivors in this litter. The Reproductive toxicity NOAEL is less than 40 mg/ kgday ( lowest dose tested). The Reproductive toxicity LOAEL is 40 mg/ kg/ day, based on increased incidence of resorptions and significantly reduced litter size.

The percentage loss of prenatal litters was 4, 13, and 22% for 0, 40, and 53.3 mg/ kg/ day, respectively. Developmental effects were evident only in litters with dams exhibiting severe respiratory signs, other females with similar respiratory effects successfully maintained apparently normal litters. The developmental effects of phenol were isolated to four litters: Three ( one from low dose group) were fully resorbed and the fourth exhibited high perinatal mortality. Postnatal loss was minimal with a small increase, less than 5%, at the high dose. Changes in pup weights were minimal and did not vary significantly from control levels. Kinked tails were also noted in one litter at 53.3 mg/ kg/ day. The Developmental Toxicity NOAEL is less than 40 mg/ kg/ day ( lowest dose tested). The Developmental Toxicity LOAEL is 40 mg/ kg/ day, based on increased incidence of perinatal loss. 7 4. Reproductive Toxicity Study Conclusions In a two generation reproduction toxicity study conducted by Ryan et al ( 2001), phenol was administered to groups of 30 Sprague Dawley rats/ sex/ dose in drinking water at concentrations of 200, 1000, or 5000 ppm ( 14, 70, and 310 mg/ kg/ day for males and 20, 93, and 350 mg/ kg/ day for females, respectively, for both generations). There were treatment related decreases in body weight and body weight gain in P1 generation rats treated with phenol compared to controls. These reductions were concomitant with decreases in food and water consumption and observed in the high dose rats. There were also treatment related decreases from controls in F1 body weight in the 5000 ppm phenol treated rats. The lower maternal body weight may have contributed to the lower birth weight of F1 generation as a result of the decreased food and water consumption during lactation and decreased palatability.

The Maternal Toxicity NOAEL is 1,000 ppm in the P1 and F1 generations. The Maternal Toxicity LOAEL is 5,000 ppm based on decreases in water and food consumption, body weight ( average 11% decrease during premating weeks 1 and 10, gestation and lactation) and body weight gain ( average 18% decrease during premating weeks 1 through 10) in the P1 and F1 generations. These effects are associated with flavor aversion to phenol in the drinking water.

There were no treatment related effects on reproductive performance in either generation ( P1 and F1). The estrus cycle, epididymal sperm count, motility, sperm morphology, testicular sperm count, and production rate were unaffected by phenol treatment in the P1 and F1 generations. However, the percent of offspring alive after PND 0 were significantly decreased in the 5000 ppm treated groups with a 10% decrease on PND 4 for the P1 generation and decreases of 28 and 24% on PND 4 and 7 21, respectively, for the F1 generation.

The Reproductive Toxicity NOAEL is greater than or equal to 5,000 ppm in the P1 and F1 generations ( highest dose tested). The Reproductive Toxicity LOAEL is greater than 5,000 ppm in the P1 and F1 generations ( not established).

There were treatment related effects for both F1 and F2 generations with increases in litter mortality ( more so in the F2 generation) and reduced offspring body weights in the high dose group. This occurred concurrently with maternal toxicity ( decreased maternal body weight); believed to be secondary to the animals' aversion to the flavor of the phenol treated water and resulted in decreased maternal as well as offspring body weight. There were delays in vaginal patency of F1 females ( 38.3 days for treated females vs. 34.6 days for control females) and preputial separation of F1 males ( 47.8 days for treated males vs. 44 days for control males) observed with decreases in pre and post weaning body weights in the high dose group. Therefore, the onset of puberty was delayed and attributed to decreased food and water consumption and reduced body weight.

The Offspring Toxicity NOAEL is 1,000 ppm. The Offspring Toxicity LOAEL is 5,000 ppm based on decreases in body weight of F1 and F2 offspring ( 5 7% on PND 0; 15 30% on PND 4 21), decreases in litter survival of P1 and F1 offspring ( P1 generation: 90% in treated animals vs. 99% in control animals on PND 4; 96% in treated animals vs. 100% in control animals on PND 7 21. F1 generation: 67% in treated animals vs. 93% in control animals on PND 4; 74% in treated animals vs. 98% in control animals on PND 7 21) and delays in 8 preputial separation in F1 males ( 47.8 days for treated males vs. 44 days for control males) and vaginal patency in F1 females ( 38.3 days for treated females vs. 34.6 days for control females).

5. Information from Literature Sources Information describing hazards of phenol were obtained mainly from published scientific literature on the toxicity of this compound, including technical reports from the National Toxicology Program ( ntp server. niehs. nih. gov) and the USEPA's IRIS website ( epa. gov/ iris) . Product chemistry data were obtained from the Handbook of Physics and Chemistry, 64th edition ( CRC Press), 1983.

6. Pre and/ or Postnatal Toxicity A. Determination of Susceptibility The ADTC concluded that there is no evidence for susceptibility of phenol from the available data on developmental and reproductive toxicity.

B. Degree of Concern Analysis and Residual Uncertainties The ADTC concluded that there are low concerns and no residual uncertainties for preand or post natal toxicity with phenol for any of the available studies. Conservative NOAELs were established for all developmental and offspring effects. The developmental and reproductive toxicity studies conducted with phenol provide adequate information on the dose response relationships for developmental and reproductive toxicity and are considered adequate studies for regulatory purposes.

C. Proposed Hazard based Special FQPA Safety Factor( s):

The hazard based default special FQPA safety factor can be removed ( 1X) when assessing dietary risks resulting from the uses of phenol.

7. Recommendation for a Developmental Neurotoxicity Study The ADTC did not recommend for a developmental neurotoxicity study. 9 HAZARD IDENTIFICATION 1. Acute Reference Dose The ADTC determined that there was no appropriate endpoint for assessment of acute dietary exposure. This conclusion was based upon examination of the hazard data which might be used in support of such an endpoint. Body weight effects observed were not considered to be the result of a single exposure. There were no other effects from the data that were reflective of an adverse effect from a single exposure. This risk assessment was not required and therefore, an Acute RfD value was not selected.

2. Chronic Reference Dose A chronic Reference Dose has been published in IRIS. This Reference Dose value is based upon an unpublished developmental toxicity study conducted according to GLP guidelines ( Argus Research Laboratories, 1997). In this study, pregnant Crl: CDRBR VAF/ Plus Sprague Dawley rats ( 25 per group) received phenol by oral gavage on GDs 6 through 15. Dosing was three times daily with 0, 20, 40, or 120 mg phenol/ kg/ dosage using a dosing volume of 10 mL/ kg. The corresponding daily doses were 0, 60, 120, and 360 mg/ kg day. The authors noted that the test material was 90% phenol United States Pharmacopeia ( USP); the authors adjusted the dosage calculations for test material purity.

One high dose dam died on GD 11. The study authors attributed this death to phenol treatment because it occurred only at the high dose, although there were no adverse clinical observations and no abnormal necropsy findings in this animal. Other high dose animals exhibited excess salivation and tachypnea ( rapid breathing). There were no other treatment related clinical observations and no treatment related necropsy findings. Dose dependent decreases in body weight of the exposed animals as compared with the controls were observed. Statistically significant decreases in both maternal body weight ( 8%) and body weight gain ( 38% for GD 6 B 16) were observed at the high dose; although a statistically significant decrease in body weight gain ( 11%) was observed at the mid dose, the decrease at the mid dose ( relative to controls) in absolute maternal weight at the end of dosing ( 3%) was not statistically significant. Dosedependent decreases in food consumption were also observed during the dosing period . Fetal body weights in the high dose group were significantly lower than those of the controls, by 5 B 7%. The high dose group had a statistically significant decrease in ossification sites on the hindlimb metatarsals, but it is unlikely that this small change is biologically significant. The incidence of litters with incompletely ossified or unossified sternal centra was 0/ 23, 0/ 25, 3/ 23, and 3/ 24; this increase was not statistically significant. There were small, dose related increases in the number of litters with fetuses with " any alteration" and with " any variation" at 120 mg/ kg/ day and higher. However, neither of these changes was statistically significant, and the response was not clearly dose related. In addition, an increase in total variations is of questionable significance in the absence of any increase in individual variations. There were no other 10 treatmentrelated effects on uterine contents, malformations, or variations.

The maternal toxicity NOAEL was 60 mg/ kg day and the maternal toxicity LOAEL was 120 mg/ kg/ day based on small decreases in maternal body weight gain. The developmental toxicity NOAEL was 120 mg/ kg day and the developmental toxicity LOAEL was 360 mg/ kg/ day based on decreased fetal body weight and delayed ossification.

The results of this study are supported by the 1983 NTP developmental toxicity study in rats, in which the maternal NOAEL and LOAEL were determined to be greater than or equal to 120 mg/ kg/ day and greater than 120 mg/ kg/ day, respectively, and the developmental NOAEL and LOAEL were determined to be 60 and 120 mg/ kg/ day, respectively.

Dose and Endpoint for Establishing cRfD: The Developmental Toxicity NOAEL of 60 mg/ kg/ day was established from the 1983 NTP developmental toxicity study in rats and is based on a significant reductions from the control in mean fetal body weight/ litter at the LOAEL of 120 mg/ kg/ day.

Chronic RfD = 60 mg/ kg = 0.6 mg/ kg 100 Comments: The developmental NOAEL of 60 mg/ kg/ day is considered sufficiently conservative as a chronic RfD value, and is also protective of infants and children being a developmental endpoint.

3. Dermal Absorption Dermal absorption data were available from the IRIS Toxicological profile for phenol. From the available data, dermal absorption percentages of 20 50% have been observed from in vivo and in vitro studies. The ADTC selected the 50% dermal absorption value for phenol for use in risk assessments as a conservative value. This value also takes into account the irritant properties of phenol which may increase its dermal absorption.

4. Incidental Oral: Short and Intermediate term Study selected: Developmental toxicty in Rats ( NTP, 1983)

In a prenatal developmental toxicity study ( Jones Price, Ledoux, Reel, et al. 1983) phenol, in distilled water, was administered to groups of 23 female CD rats/ dose by gavage at dose levels of 0, 30, 60, or 120 mg/ kg/ day from gestation days ( GD) 6 to 15. Females were weighed daily during treatment 11 and observed for clinical signs of toxicity. A total of 20 23 females/ group were confirmed to be pregnant at sacrifice on GD 20. The gravid uterus of each dam was weighed and the urine contents examined for implantation sites and fetus vitality ( live, dead, or reabsorbed). Each live fetus was weighed and examined for external, visceral, and skeletal malformations.

There were no treatment related clinical signs, increases in mortality ( 100% survival), or decreases in body weight and body weight gain in rats dosed with phenol. The Maternal toxicity NOAEL is greater than or equal to 120 mg/ kg/ day ( highest dose tested). The Maternal toxicity LOAEL is greater than 120 mg/ kg/ day ( not established).

There were no changes in reproductive parameters in treated animals when compared to controls. The Reproductive toxicity NOAEL is greater than or equal to 120 mg/ kg/ day ( highest dose tested). The Reproductive toxicity LOAEL is greater than 120 mg/ kg/ day ( not established).

There were no treatment related effects on mean live fetal body weight/ litter in the low and mid dose treated groups. However, a significant reductions from the control in mean fetal body weight/ litter was observed in the high dose ( 120 mg/ kg/ day) group. There was no evidence of teratogenicity observed in the rats following administration of phenol. The Developmental toxicity NOAEL is 60 mg/ kg/ day. The Developmental toxicity LOAEL is 120 mg/ kg/ day, based on reduced fetal weight.

Endpoint for risk assessment: The Developmental Toxicity NOAEL of 60 mg/ kg/ day was established from the developmental toxicity study in rats ( Jones Price, Ledoux, Reel, et al. 1983) based on a significant reduction from the control in mean fetal body weight/ litter at the LOAEL of 120 mg/ kg/ day.

Comments: The endpoint selected is appropriate for the route and duration of this risk assessment. In addition, the developmental toxicity NOAEL of 60 mg/ kg/ day is considered conservative and protective of infants and children. Effects observed in the Narotsky and Kavlock study ( 1995, described above in the developmental toxicity conclusions section) at 53 mg/ kg/ day provide support for the selection of the 60 mg/ kg/ day as an endpoint value.

5. Dermal Exposure: Short and Intermediate term Study selected: See Incidental Oral: Short and Intermediate Term Endpoint for risk assessment: The Developmental Toxicity NOAEL of 60 mg/ kg/ day was established from the developmental toxicity study in rats ( Jones Price, Ledoux, Reel, et al. 1983) based on a significant reduction from the control in mean fetal body weight/ litter at the LOAEL of 120 mg/ kg/ day. Effects observed in the Narotsky and Kavlock study ( 1995, described above in the developmental toxicity conclusions section) at 53 mg/ kg/ day provide support for the selection of the 60 mg/ kg/ day as an endpoint value.

Comments: A dermal absorption factor of 50% should be used since an oral endpoint was selected. An uncertainty factor of 100 is employed for this risk assessment ( 10x interspecies extrapolation, 10x intraspecies variation) 12 6. Dermal Exposure: Long term The volatile nature of phenol along with the short half life of the chemical is not expected to result in chronic dermal exposure to the chemical. Therefore, the ADTC did not select a long term dermal endpoint for the chemical and this risk assessment is not required.

7. Inhalation Exposure ( All durations)

Study Selected: Dalin and Kristofferson: Physiological Effects of a Sub lethal Concentration of Inhaled Phenol on the Rat. Ann. Zool. Fennici 11: 193 199, 1974 Executive Summary ( from the IRIS update): In a study published by Dalin and Kristoffersson ( 1974), seven white rats of an in house strainwere exposed to phenol at a concentration of 100 mg/ m3 continuously for 15 days. There is some uncertainty about this exposure measure, however, because the exposure chamber was not set up according to modern designs, and it does not appear that continuous monitoring of exposure levels was conducted. Unexposed rats ( n = 11 B 12) were used as controls. Nervous system effects were observed from the first day after the start of exposure. These effects progressed from increased activity to imbalance, twitches, and disordered walking rhythm on days 3 B 4. These signs disappeared by day 5 and were replaced by sluggish behavior until the end of the exposure. A tilting plane test was conducted before and after exposure in both groups, and a significant effect was observed on the exposed rats. There were no significant changes in food intake or water consumption during the exposure period. Although there was no significant difference in body weight of the exposed group compared with that of the controls, the average body weight of the exposed group decreased during exposure, whereas the controls gained weight. The serum biochemical evaluations showed large, statistically significant increases in SGOT, SGPT, lactic dehydroganese ( LDH), and glutamate dehydrogenase activities, indicating liver damage.

Plasma potassium and magnesium levels were also increased. Although the significance of these changes is unknown, the authors suggested that the increased magnesium levels may have caused some of the nervous system effects. Hemoglobin and hematocrit were unaffected. No histopathology examination was conducted. On the basis of the observed nervous system effects as well as the serum enzyme changes indicating liver damage, the only exposure concentration was a free standing LOAEL.

Endpoint used for risk assessment: LOAEL of 0.1 mg/ L, based on alterations in sliding angle from tilting plane test, and significant increases in liver enzymes. An uncertainty factor of 300 is applied to this risk 13 assessment for short and intermediate term risk assessments ( 10x interspecies extrapolation, 10x intraspecies variation, 3x for use of a LOAEL). For long term risk assessments, an uncertainty factor of 1000 is applied to the risk assessment ( 10x interspecies extrapolation, 10x intraspecies variation, 3x for use of a LOAEL, 3x for lack of a long term study). The IRIS Toxicological review also notes that an adequate subchronic inhalation toxicity study for phenol is not available.

CLASSIFICATION OF CARCINOGENIC POTENTIAL The updated toxicological review in the EPA IRIS database ( USEPA, 2002) provides a summary of the weight of the evidence with respect to the carcinogenic potential of phenol, and this is reproduced in part below.

Chronic drinking water bioassays of phenol have been conducted in rats and mice ( NCI, 1980). In these studies, NCI concluded that phenol was " not carcinogenic" in male or female F344rats or B6C3F1 mice. However, the report also noted that leukemia and lymphoma were statistically significantly increased in low dose male rats, although there was no significant increase at the high dose. The increases in leukemia are of particular interest in light of the leukemogenic effects of benzene ( for which phenol is a metabolite) in humans. ( In experimental animals, benzene has not been shown to induce leukemia, although increases in lymphoma have been observed [ e. g., NTP, 1986].).

In contrast with the negative results for oral carcinogenicity, dermally administered phenol has been consistently observed to be a promoter. Several authors ( Salaman and Glendenning, 1957; Boutwell and Bosch, 1959; Wynder and Hoffmann, 1961) observed that dermally applied phenol promoted DMBA initiated skin tumors. These studies have generally reported significant skin ulceration at all phenol doses tested. The exception is Wynder and Hoffman ( 1961), who reported that 5% phenol promoted DMBA initiated tumors in mice in the absence of any toxic reactions. When the same phenol dose was administered in different volumes, higher promotion activity was exhibited by the more concentrated solution, which also produced severe skin ulceration, suggesting that some of the promotion activity may have been related to the rapid cell division of repair of skin damage ( Salaman and Glendenning, 1957).

A more recent study of the tumor promoting ability of phenol was conducted by Spalding et al. ( 1993). In this study, a transgenic mouse line having the properties of genetically initiated skin and sensitive to TPA, a well described promotor of skin papillomas in two stage models, were treated topically 2 times per week for up to 20 weeks with several chemicals including phenol. Papillomas were induced with the chemicals benzoyl peroxide, TPA, and 2 butanol peroxide. Three mg of phenol administered for 20 weeks resulted in a single papilloma in one of five male mice at 7 weeks and persisted over the 20 week treatment period. This response was not statistically significant compared to controls.

A mechanistic study conducted by Stenius et al. ( 1989) was designed to assess the toxicity and carcinogenicity of phenol when administered to partially hepatectomized male SD rats. Phenol was administered by gavage 5 days/ week for 7 weeks at a concentration of 100 mg/ kg/ day. Animals were sacrificed, by decapitation, 1 week after last treatment. Sections of the rat liver were prepared and stained to measure for induction of   glutamyltranspeptidase ( GGT) positive enzyme altered foci as an 14 indicator of tumor initiation. Additional studies involved single oral administrations of phenol to measure inductions of hepatic ornithine decarboxylase ( ODC), glutathione ( GSH) depletion, and in vivo lipid peroxidation.

Phenol did not increase the number or volume of foci and was found to have no tumor initiating properties within the confines of this study. Lipid peroxidation was not induced following administration of phenol as measured by malondialdehyde ( MDA) in the urine. There were small and inconsistent effects observed in hepatic ornithine decarboxylase ( ODC) in which there was an increase at the middose but a decrease at the high dose. Observed measurements of hepatic ODC were 18.8, 32.3, and 11.4 pmol/ mg/ h for the phenol doses of 0, 50, and 100 mg/ kg/ day, respectively. Phenol did not induce GSH depletion in hepatocytes.

MUTAGENICITY A summary of mutagenicity studies conducted with phenol is shown below.

Study Type Results Bacterial reverse mutation ( Ames test). Toxicology 18: 219 232 Negative. There was no evidence of induced mutant colonies over background. Positive controls produced the appropriate responses in the corresponding strains of the bacterial reverse mutagenesis test.

Bacterial reverse mutation ( Ames test). Env. Mutagenesis 1: 3 142 Negative. There was no evidence of induced mutant colonies over background. Positive controls produced appropriate responses in corresponding strains of the bacterial reverse mutagenesis test.

Bacterial reverse mutation ( Ames test). Mutation Res. 90: 91 109 Negative. No evidence of induced mutant colonies over background following administration of phenol in the absence of metabolic activation. Mutant colonies increased following treatment with phenol in the presence of metabolic activation. Phenol was not mutagenic in the bacterial strains in the absence of metabolic activation. Phenol showed mutagenic effects as measured by a significant increase over control in histidine revertants , in the presence of metabolic activation, predominantly in the Ames tester strains of S. typhimurium that are sensitive for frameshift mutatgens ( ie., TA 98)

Bacterial reverse mutation ( Ames test). Food Chemistry and Toxicology 20: 383 391 Negative. Phenol did not significantly induce mutant colonies over background. The number of histidine revertants scored in the presence of phenol never more than slightly exceeded the number of spontaneously arising revertants.

Bacterial reverse mutation ( E coli). Mutation Res. 105: 309 312 Negative. No evidence of mutagenicity based on results that phenol did not induce filamentation in the E. coli Ion

strain. 15 In vivo gene mutation assay ( Drosophila). Mutation Res. 90: 91 109 Negative. Phenol was administered to D. melanogaster and 3543, 3458, and 2139 chromosomes were tested for sex linked recessive lethals in Broods 1, 2, and 3, respectively. There were no significant increases in recessive lethals observed following administration of phenol to Broods 1, 2, and 3 and only 17 ( 0.48%), 6 ( 0.17%), and 7 ( 0.33%) sex linked recessive lethals, respectively, were measured in the chromosomes tested. Although the frequency of recessive lethals was increased, these changes did not achieve statistical significance. Phenol was not mutagenic within the confines of this study.

In vivo gene mutation assay ( Drosophila). Env. Mutagenesis 7: 677 702 Negative. Phenol was tested up to cytotoxic concentrations 2000 and 5250 ppm in feeding and injection studies, respectively. The number of sex linked recessive lethal mutations in the feeding study were 7 and 11 at the 0 and 2000 ppm doses, respectively. The injection assay resulted in 5 ( 0 ppm) and 6 ( 5250 ppm) sex linked recessive lethal mutations, while the feeding study exhibited 0.12 ( 0 ppm) and 0.17 ( 2000 ppm) lethals. These sex linked recessive lethal mutations were not significantly different from those found in controls.

In vitro mammalian cells in culture ( L5178Y). Mutation Res. 104: 389 393 Positive. Phenol, in ethanol, was administered to CHO V79 cells individually at concentrations of 0, 25, 50, 100, 250, or 500 µ g/ mL and in a mixture with 12 µ g/ mL of benzo[ a] pyrene at concentrations of 100, 250, or 500 µ g/ mL for 2 hours. Evidence of mutagenicity was exhibited by the statistically significant increase in the frequency of 8 azaguanine resistant mutants over the spontaneous level at phenol concentrations of 250 and 500 µ g/ mL In vitro chromosome aberration. Cancer Res. 53: 1023 1026 Positive. Phenol was administered to preincubated HL60 cell cultures. The cells were exposed to phenol for 30 minutes at a concentration of 100 µ M. Phenol at a concentration of 100 µ M produced a 3.5 fold increase of 8OHdGua levels in DNA in HL60 cells after 30 minutes of incubation. Phenol induced rapid 8OHdGua formation in HL60 cells that returned to normal levels following further incubation presumably due to the rapid repair of DNA damage Spermatogonial chromosome aberration assay. Folia Morphology 36: 13 22. Positive. Structural aberrations in chromosomes of reproductive cells of male and female mice of the Porton strain were investigated using phenol. Phenol was mutagenic in the Porton strain mice due to the evidence of a concentration related ( 0.08 8.0 mg/ L/ day) positive response of spermatogonial chromosome aberrations following 30 days of exposure to phenol in water.

Micronucleus assay in mouse bone marrow. Mutation res. 244: 15 20 Negative. Mutagenicity of individual and combined administrations of phenol and hydroquinone were investigated by examining the induction of micronucleated polychromatic erythrocytes ( MNPCEs) in Swiss CD 1 male mice bone marrow cells. The administration of phenol at concentrations 40 160 mg/ kg bw did not result in micronuclei induction in the mouse bone marrow cells; therefore, phenol was not genotoxic in this assay. 16 DATA GAPS / REQUIREMENTS The toxicity data base for Phenol/ Sodium Phenate is considered complete and there are no toxicology data gaps for this active ingredient. 17 ACUTE TOXICITY The acute toxicity of phenol had been described in the open scientific literature and from studies submitted to the Office of Toxic Substances.

The acute oral toxicity of phenol has been described in IRIS as varying widely, from doses of 14 mg/ kg to 930 mg/ kg ( USEPA, 2002). Data assembled by the Antimicrobials Division shows oral LD 50 values in the range of 297 1120 mg/ kg, which corrorborates to some extent the results reported in IRIS. Acute dermal toxicity of phenol as reported in IRIS showed a dermal LD 50 of 669.4 mg/ kg from application of undiluted phenol for 24 hours to the skin of rats ( Conning and Hayes, 1970). Decreasing the concentration of phenol appears to result in higher dermal LD 50 values; for example, application of a 50% aqueous solution showed an LD 50 value of 2350 mg/ kg ( OTS # 0515564/ 86 070001402). Data on acute inhalation toxicity of phenol are limited. In a study submitted to OTS ( OTS# 0515567/ 86 870001405), rats were exposed for 8 hours to 2.5 L/ min of 100% phenol, with no mortality reported. In a two week inhalation toxicity study, neurotoxicity was observed at a concentration of 0.1 mg/ L but no mortality was observed.

Phenol has been shown to be a significant eye and skin irritant. In a study submitted to OTS ( OTS # 0515567/ 86 870001405), severe damage to the cornea was observed after instillation of a 15% and 5% solution of 100% phenol into the eyes of rats. In another study ( Flickinger, 1976), instillation of 0.1g phenol into the eye of male rats produced inflammation of the conjunctiva, corneal opacity, with no improvement over 14 days post dose. Primary dermal irritation studies submitted to OTS ( OTS #' s 0515564/ 86 070001402 and 0515567/ 86 870001405) showed mild to marked erythema. The only dermal sensitization study was performed with Happy Jack Mange medicine where the % a. i. was not reported, but results indicated strong sensitization ( HED document # 010599).

Acute Toxicity Profile for Phenol/ Sodium Phenate Guideline Number Study Type/ Test substance (% a. i.) MRID Number/ Citation Results Toxicity Category 870.1100 ( § 81 1) Acute Oral Rat Phenol purity > 99% Berman, et al. 1994 LD50 = 400 ( 297 539) mg/ kg/ day II 870.110 ( § 81 1) Acute Oral  Rat Phenol purity 100% OTS #  0515567 86 870001405 LD50 = 1030 ( 940 1120) mg/ kg/ day III 870.1100 ( § 81 1) Acute Oral Rat Phenol purity not reported Flickinger. 1976 LD50 = 650 ( 490 860) mg/ kg/ day III 870.1200 ( § 81 2) Acute Dermal Rat Phenol purity not reported Brown, et al. 1975 LD50 ( Non occluded) = 0.68 ( 0.57 0.78) mL/ kg LD50 ( Occluded) = 0.50 mL/ kg II Guideline Number Study Type/ Test substance (% a. i.) MRID Number/ Citation Results Toxicity Category 18 870.1200 ( § 81 2) Acute Dermal Rabbit Sodium Phenate purity 57% OTS #  0515564 86 870001402 LD50 = 2350 ( 1880 2940) mg/ kg/ day III 870.1200 ( § 81 2) Acute Dermal Rabbit Phenol purity 100% OTS #  0515567 86 870001405 LD50 = 0.63 ( 0.56 0.70) mL/ kg II 870.1200 ( § 81 2) Acute Dermal Rat Phenol purity laboratory reagent grade Conning, et al. 1970 LD50 = 669.4 mg/ kg/ day II 870.1200 ( § 81 2) Acute Dermal Rabbit Phenol purity not reported Flickinger. 1976 LD50 = 850 ( 600 1200) mg/ kg/ day II 870.1300 ( § 81 3) Acute Inhalation Rat Phenol purity 100% OTS #  0515567 86 870001405 No deaths occurred at 2.5 L/ min for 8 hours Not established 870.1300 ( § 81 3) Acute Inhalation Rat Phenol purity not reported Flickinger. 1976 No deaths occurred at 900 mg/ m3 for 8 hours Irritation and timerelated CNS effects Not established 870.2400 ( § 81 4) Acute Eye Irritation Rabbit Sodium Phenate purity 57% OTS #  0515564 86 870001402 15% solution caused corneal necrosis and conjunctiva lesions II 870.2400 ( § 81 4) Acute Eye Irritation Rabbit Phenol purity 100% OTS #  0515567 86 870001405 Severe damage to the cornea at 15% and lesser damage in 5% Not established 870.2400 ( § 81 4) Acute Eye Irritation Rabbit Phenol purity not reported Flickinger. 1976 Dose not provided. Severe conjunctiva, iritis, corneal opacities and ulcerations with no improvement after 14 day observation period. I 870.2500 ( § 81 5) Acute Dermal Irritation Rabbit Sodium Phenate purity 57% OTS #  0515564 86 870001402 Mild to marked erythema and marked capillary injection were observed in 50% of animals tested II 870.2500 ( § 81 5) Acute Dermal Irritation Rabbit Phenol purity 100% OTS #  0515567 86 870001405 10% solution caused moderate to marked erythema Not established 870.2500 ( § 81 5) Acute Dermal Irritation Rabbit Phenol purity not reported Flickinger. 1976 Corrosive I 19 VIII. SUMMARY OF TOXICOLOGY ENDPOINT SELECTION Summary of Toxicological Dose and Endpoints for Phenol Exposure Scenario Dose ( mg/ kg/ day) used in risk assessment UF Special FQPA SF and Level of Concern for Risk Assessment Study and Toxicological Effects Acute Dietary ( gen population) This risk assessment is not required.

Acute Dietary ( females 13 49) This risk assessment is not required.

Chronic Dietary ( all populations) NOAEL= 60 UF = 100 Chronic RfD = 0.6 mg/ kg/ day 100X Developmental toxicity study in rats ( NTP, 1983) Based on significant reductions from the control in mean fetal body weight/ litter at 120 mg/ kg/ day.

Incidental Oral Short Term ( 1  30 Days)

Residential Only NOAEL= 60 mg/ kg/ day MOE = 100 Developmental toxicity study in rats ( NTP, 1983) Based on significant reductions from the control in mean fetal body weight/ litter at 120 mg/ kg/ day.

Incidental Oral Intermediate Term ( 1  6 Months)

Residential Only NOAEL= 60 mg/ kg/ day MOE = 100 Developmental toxicity study in rats ( NTP, 1983) Based on significant reductions from the control in mean fetal body weight/ litter at 120 mg/ kg/ day.

Dermal1 Short and intermediate term NOAEL = 60 mg/ kg/ day MOE = 100 Developmental toxicity study in rats ( NTP, 1983). Based on significant reductions from the control in mean fetal body weight/ litter at 120 mg/ kg/ day.

Inhalation2 All durations LOAEL = 0.1 mg/ L MOE = 300 ( ST, IT)

MOE = 1000 ( LT) Dalin and Kristofferson: Physiological Effects of a Sub lethal Concentration of Inhaled Phenol on the Rat. Ann. Zool. Fennici 11: 193 199, 1974 LOAEL of 0.1 mg/ L, based on alterations in sliding angle from tilting plane test, and significant increases in liver enzymes Cancer data inadequate for assessment of human carcinogenic potential ( USEPA, 2002)

1a dermal absorption factor of 50% should be used since an oral endpoint was selected.