1

MEMORANDUM

TO: Megan Carroll

Acting Division Director Environmental Analysis Division

CC: Daniel Bushman, Ph.D.

Analytical Support Branch

, Environmental Analysis Division

FROM: Jocelyn Hospital

Acting Branch Chief/ Toxicologist Analytical Support Branch, Environmental Analysis Division

DATE: July 24 , 2015

SUBJECT: Review of the Data in the 2010 Integrated Risk Information System ( IRIS )

Toxicological Review of Ethylene Glycol Monobutyl Ether (EGBE)

EPA’s evaluation of the toxicity of ethylene glycol monobutyl ether ( EGBE ) included a review of the 2010 Integrated Risk Information System ( IRIS ) toxicological review of EGBE (U.S. EPA 2010) . EPA also reviewed the findings of studies published since publi cation of the IRIS toxicological review of EGBE, but EPA found no data relevant to include in this evaluation. Below is (1) a summary of the evidence of EGBE’s human health toxicity from the 2010 IRIS toxicological review of EGBE and (2) the conclusions reached regarding EGBE’s potential toxicity to humans under Section 313 of the Emergency Planning and Community Right

- to

Know Act (EPCRA).

Summary of the 2010 IRIS Toxicological Review of EGBE :

1. Toxicokinetics

. In humans, EGBE is absorbed and rapidly distributed following inhalation, ingestion, or dermal exposure (Kumagai et al. 1999; Johanson and Bohman 1991; Corley et al. 1994; Corley et al. 1997). Several reviews have described the metabolism of EGBE in detail (Commonwealth of Australia, 1996; ECETOC, 1994; EU 20 06 ). The principal products from EGBE met a bolism are butoxyacetic acid (BAA) ( rats and humans ) and the glutamine or glycine conjugate of BAA (humans only ). Other metabolic products, such as the glucuronide conjugate of EGBE, ethylene glycol, butoxyacetaldehyde, and carbon dioxide are minor metabolites or are transitory in nature (e.g., butoxyacetaldehyde) and do not accumulate in blood, tissues, or excreta. A lcohol dehydrogenase and O

- dealkylation by a cytochrome P450 dealkyla se (CYP 2E1) are the two main pathways of EGBE metabolism observed in rats . BAA is excreted in the urine of both rats and humans, which suggests that the creation of BAA through the formation of butoxyacetaldehyde by alcohol dehydrogenase is applicable to rats and humans ( Corley et al. 1997; Corley et al. 2005; Medinsky et al. 1990 ). The other proposed metabolic pathways , however, may only be applicable to rats since the metabolites of these pathways (i.e., ethylene glycol, EGBE glucuronide, and EGBE sulfat e) have been2

observed in the urine of rats ( Bartnik et al. 1987; Ghanayem et al. 1987), but not i n humans ( Corley et al. 1997). In addition, Corley et al. (1997) confirmed the finding from Rettenmeier et al. (1993) that approximately two

- thirds of the BAA formed in humans is conjugated with glutamine and glycine. These pathways, however, have not been observed in the rat. Please refer to Figure 3

- 1 in the 2010 IRIS toxicological review of EGBE (U.S. EPA 2010) for the proposed metabolic scheme of EGBE in rats and humans.

Several experimental studies have measured the concentration of BAA in human serum and urine following exposure to EGBE. For humans the elimination kinetics of EGBE and BAA appear to be independent of the route of exposure

, with an approximate half

life of around one hour for EGBE and an approximate half

- life of BAA of 3

– 4 hours (Johanson 1986; Johanson and Johnsson 1991; Johanson et al. 1988). In a study of 31 male wo rkers exposed to 2.91 ± 1.30 mg/m 3 (0.59 ± 0.27 ppm) EGBE , Haufroid et al. (1997) reported average post shift urine BAA concentrations of 10.4 mg/g creatinine. In a study of 5 healthy male humans exposed to 20 ppm EGBE for 2 hours during light exercise , Jo hanson and Johnsson (1991) reported an a verage peak blood concentration of 45 μM BAA (range of 30 to 60μM) 2

– 4 hours after exposure

. The authors also reported a low renal clearance of BAA relative to the glomerular filtration rate, indicating binding of BAA to blood proteins. Laitinen ( 1998 ) measured BAA levels in 8 silkscreen printers exposed to a mixture of EGBE and 2

- butoxyethylaceta te. He reported a daily mean 8

- hour air concentration ranging from 0.1 to 0.6 ppm over a 5

- day period. Urine samples from these workers contained an average of 75 mg BAA/g creatinine immediately after their shift and 58 mg BAA/g creatinine 14

– 16 hours po st

- exposure. Please refer to Table 3

- 1 in the 2010 IRIS toxicological review of EGBE (U.S. EPA 2010) for a summary of species

- specific toxicokinetic parameters.

Several physiologically based pharmacokinetic models for EGBE have been developed. Some older models have described the kinetics of EGBE for acute human exposure and exposure to rats via the ingestion , inhalation, and dermal routes (Johanson 1986; Shyr et al. 1993 based on data from Medinsky et al. 1990 and Sabourin et al. 1992; 1993 )

. Newer models have extended upon th e work of these previous models. Corley et al. ( 1994 ) described the kinetics of EGBE and BAA in both rats and humans. These authors later validated the human dermal exposure model (Corley 1997). Lee et al. (1998) modeled the kinetics of EGBE and BAA in mice and rats from an NTP 2

- year inhalation bioassay (based on data from Dill et al. 1998). Species, gender, age, and exposure concentration

dependent differences in the kinetics of BAA were observed

. Corley et al. ( 2005 ) built on the Le e et al. (1998) model by replacing some model assumptions with experimenta l data (Note: t he Corley et al. (2005) model, along with the Lee et al. (1998) rat and mouse model and Corley et al. (1997) human model were used by EPA to calculate internal dose s o f EGBE in the 2010 IRIS toxicological review of EGBE (U.S. EPA 2010) )

.

2. Effects of Acute and Short

- Term Exposure

. Hematol o gic and other effects have been observed in s everal acute and short

- term oral studies in animals

. Ghanayem et al. ( 1987) reported a lowest

- observed

- adverse

- effect level ( LOAEL ) of 32 mg/kg/ day based on increased hemoglobin concentrations in the urine and associated hemolytic effects at higher doses for both young and adult F344 rats ( number not specified) after a single3

gavage dose of EGBE . Hemolysis and decreases in hemoglobin concentration s and red blood cell counts were also reported at 250 mg/kg/ day, the only dose tested, in an acute oral t oxicity study in male F344 rats ( number not specified) (Ghanayem and Sullivan 1993). Grant et al. (1985) reported a LOA E L of 500 mg/kg/ day, the lowest dose tested, b ased on hemolytic anemia, reticulocytosis

, and increased hematopoiesis in male F34 4
rats (N = 24) after administering EGBE by gavage for 4 days

. Ghanayem et al. ( 1992 ) observed similar effects after administering 125 mg/kg/ day EGBE to male F344 rats (N = 6) for 12 days. These effects included : significant hemolysis, increased mean corpuscular volume

, increased ATP concentration, increased reticulocyte counts, and increased relati ve splee n

- to

- body weight ratios. Gradual recovery, however, was observed over the course of treatment.

Other studies have investigated the impact of EGBE on specific organs and cells. Ezov et al. (2002) exposed male and female F344 rats (N = 4) to d aily doses of 250 mg/kg/ day EGBE . These authors reported s ignificant morphological changes in red blood cells in both males and females

, with disseminated thrombosis and infarction mainly observed in females consisting of necrosis in several organs . Renal tubular necro sis with hemoglobin
casts was observed in both males and females. Koshkaryev et al. (2003) found that EGBE exposure did not affect red blood cell aggregability, and its effect on deformability was inconclusive. EGBE did, however, enhance red blood cell adh erence to endothelial cells. Adherence was highest on day 2 (the first day examined) and decreased over time. Shabat et al. (2004) concluded that in EGBE

- treated rats, interactions of several factors may generate a thrombotic crisis, such as the release of procoagulant facto rs from destroyed red blood cells . These authors also concluded that disturbed blood flow may result from alterations in the rheology of red blood cells , including self

- aggregation, deformation, and adherence to the endothelium of the bl ood vessel wall. Redlich et al. (2004) observed necrosis in the dental pulp of incisors and molars and m uscle

- ce ll damage in the tongue in EGBE

- treated rats. The observed effects were likely the result of ischemia in the blood vessels supplying these tissues, rather than a direct cytotoxic effect of EGBE.

A few short

- term studies in mice have also been conducted. Corley et al. (1999) administered neat EGBE to male and female mice (N = 5) via gavage (no vehicle) f or one week at doses of 100, 400, or 800 mg/kg/day. The dose in the 100 mg/kg/ day gro up was increased to 1,200 mg/kg/ day after 2 days. Severe hemolysis and mortality were seen, and the 2

- week study was terminated after only four doses. Forestomach lesions consisting of focal areas of irritation and epithelial hyperplasia were seen at all exposure levels in this study. Poet et al. (2003) exposed male and female B6C3F1mice (N = 16) by
gav age to 400, 800, or 1,200 mg/kg/ day of EGBE for 2 days. High levels of m ortality occurred, after which the doses were halved and then discontinued when survival did not improve. Epithelial hyperplasia and inflammation of the forestomach were observed in males and females at the higher doses. Mild epithelial hyperplasia was obs erved in males and females at the lower doses. Green et al. (2002) administered a single, daily gavage dose of either EGBE or BAA (0, 50, 150, or 500 mg/kg) to female B6C3F1 mice (N = 5) for 10 days. Mice were sacrificed 18 hours after the la st dose to obs erve cell proliferation in the forestomach and glandular stomach. The authors reported a thickening of the keratinized layers or hyperkeratosis of the forestomac h (statistics not reported), but a no

-4

observed

- adverse

- effect level (N OAEL ) of 500 mg/kg EGB E and 150 mg/kg BAA was reported

.

A few studies investigated the effect of EGBE on guinea pigs. Shepard (1994) administered a 2,000 mg/kg oral dose of EGBE to guinea pigs, which resulted in complete mortality of females and 60% mortality in males. A dose of 1,000 mg/kg resulted in a 20% mortality in both males and females. Clini cal signs and gross necropsy indicated toxicity was due to irritation of the stomach. No evidence of hemolytic toxicity was reported. Gingell et al. (1998) investigated the acute oral and inhalation toxicity of EGBE in guinea pigs. They administrated 2,000 mg/kg of EGBE by gavage to 5 male and female guinea pigs, resulting in excessive mortality in both genders. The authors then administered lower doses of 500 or 1,000 mg/kg. The acute oral median lethal dose was determined to be 1,414 mg/kg for both gender s. No evidence of hematologic effects were reported. In the acute inhalation study, the median lethal concentration for a 1

- hour exposure for guinea pigs was > 633 ppm in males and > 691 ppm in females, as no effects were reported after exposure to 633 ppm or 691 ppm of EGBE, respectively.

Additionally, rats and rabbits exhibit varying degrees of hematotoxicity following dermal application of EGBE (Bartnik et al. 1987; Tyler 1984). EGBE has also been found to be an ocular irritant when instilled in rabbit s (Jacobs and Martens 1989; Kennah et al. 1989).

A few in vitro studies have investigated EGBE’s potential hemolytic effects in human red blood cells after acute exposures. Bartnik et al. (1987) reported no hemolysis of human red blood cells exposed for t hree hours to BAA levels up to 15 millimolar ( mM )

. Hemolysis was observed in rat red blood cells , however, at BAA levels as low as 1.25 mM. Udden (2000) incubated human red blood cells with up to 2.0 mM BBA for four hours , and the authors observed none of the morphol ogical changes observed in rat red blood cells at the same concentration

. Udden (2002) reported a significant change in human red blood cell deformability at exposure to 7.5 and 10 mM BAA for 4 hours, whereas deformability in rat red blood cells was significantly increased at 0.05 mM BAA. Mean cellular volume in human blood samples was significantly increased at 10 mM BAA while mean cellular volume in rats was significantly increased at 0.05mM BAA.

There are a number of case reports of acute ing estion of EGBE with little or no hematologic effects observed (Bauer et al. 1992; Gijsenbergh et al. 1989; Gualtieri et al. 1995; 2003; Rambourgh

- Schepens et al. 1988; Burkhart and Donovan 1998; Osterhoudt 2002; Dean and Krenzelok 1991). Some other observe d effects were likely not directly related to hemolysis; however, the cause of the effects cannot be explained based on the limited data available. Also, hemodialysis was employed to remove un

- metabolized EGBE in many of the cases.

One experimental study in humans (Carpenter et al. 1956)

, observed no effects on red blood cell fragility after exposure of two males and one female to up to 195 ppm EGBE for 8 hours.5

3. Carcinogenicity. Under the Guidelines for Carcinogen Risk Assessment (U.S. EPA 2005) , there is suggestive evidence of EGBE’s carcinogenic potential

. In a 2

- year chronic bioassay, NTP (2000) exposed male and female F344 rats to 31, 62.5, or 125 ppm EGBE (150, 302, 604 mg/m 3 ). This study also exposed male and female B6C3F1 mice to 62.5, 125, or 250 ppm EGBE (302, 604, 1208 mg/m 3 ). The authors concluded that there was no evidence of carcinogenic activity in male F344 rats and equivocal evidence of carcinogenic activity in female F344 rats based on increased combined incidences of benign (m ainly) and malignant pheochromocytoma of the adrenal medulla at 125 ppm ( approximately 113 mg/kg/ day using the spe cies

- specific chronic reference values for inhalation rate and body weight from U.S. EPA 1988 1 )

. However, given the marginal dose response, lack of tumor evidence in any other organ, and difficulty in distinguishing pheochromocytomas from nonneoplastic adrenal medullary hyperplasia, this tumor could not be given significant weight in assessment of EGB E’s potential carcinogenicity . The NTP (2000) study also concluded that there was some evidence of carcinogenic activity in male B6C3F1 mice based on increased incidences of hemangiosarcoma of the liver at 250 ppm and an increase in the incidence of hepatocellular carcinoma at 125 and 250
ppm ( approximately 182 and 363 mg/kg/ day, respectively, using the spe cies

- specific chronic reference values for inhalation rate and body weight from U.S. EPA 1988) . There was also some evidence of carcinogenic activi ty in female B6C3F1 mice based on an increased incidence of forestomach squamous cell papilloma (mainly) or carcinoma at 250 ppm ( approximately 365 mg/kg/ day using the spe cies

- specific chronic reference values for inhalation rate and body weight from U.S. EPA 1988)

.

4. Mutagenicity. EGBE has been tested for its potential for genotoxicity both in vitro and in vivo . Available data do not suggest that EGBE is mutagenic or clastogenic (Zeiger et al. 1992; Gol lapudi et al. 1996; Chiewchanwit and Au 1995; Klaunig and Kamendulis 2005; NTP 1996; Keith et al. 1996). While two studies reported weak genotoxicity
responses in vitro at toxic doses (Elias et al. 1996; Hoflack et al. 1995), these findings are questionabl e in light of the limited published information provided in the studies.

5. Reproductive and Developmental Toxicity. The reproductive and developmental toxicity of EGBE has been investigated in a number of oral and inhalation studies in rats, mice, and rabbits. In a two

- generation reproductive toxicity study, fertility was reduced in mice at very high maternally toxic doses (>1,000 mg/kg) ( Heindel et al. 1990), but no other significant reproductive effects were reported in any study ( Nagano et al. 1979; 1984; Dodd et al. 1983; Doe 1984; Gr ant et al. 1985; Foster et al. 1987; Exon et al. 1991; NTP 1993; 2000). Maternal toxicity related to the hematologic effects of EGBE and relatively minor developmental effects have been reported in developmental studies (Nelson et al . 1984; Tyl et al. 1984; Hardin et al. 1984; Wier et al. 1987 ). No teratogenic

1 Approximate m g/kg/ day = ( d ose in mg/m 3 * species

- specific inhalation rate) /(s pecies

- specific body w eight) * ( duration of e xposure)

Example conversion of chronic inhalation by F344 female rats at 604 mg/m 3

, 6 hours/day and 5 days/week : ( 604 mg/m 3 * 0. 24 m 3 /day)/(0. 229 kg) * (0.178) = 113 mg/kg/ day6

effects were noted in any of the studies. As such , EGBE is not reasonably anticipated to be a reproductive or developmental toxicant at moderately low to low doses

.

6. Neurotoxicity. There is no evidence of neurotoxicity in any animal studies o f EGBE. One case study patient demonstrated neurologic deficits after ingesting a product with a high dose of EGBE and other chemicals (Burkhart and Donovan 1998). Given the general limitations of case studies and the presence of other chemicals, however, EPA cannot draw conclusions about EGBE’s potential neurotoxicity from this particular study.

7. Other Chronic Toxicity. Hematologic effects and liver toxicity have been observe d at low doses of EGBE in several animal studies.

NTP (1993) conducted a 13

- week study in F344 rats and B6C3F1 mice in which groups of 10 animals/gender/species received EGBE in drinking water at doses of 0, 750, 1,500, 3,000, 4,500, and 6,000 ppm. T he corresponding doses in mg/kg/ day, based on measured drinking water consumption were: 0, 69, 129, 281, 367, or 452 mg/kg/ day in male rats; 0, 82, 151, 304, 363, or 470 mg/kg/ day in female rats; 0, 1 18, 223, 553, 676, or 694 mg/kg/ day in male mice; and 0, 18 5 , 370, 676, 861, or 1,306 mg/kg/ day in female mice.

Indications of mild to moderate anemia were observed in both genders

. Statistically significant hematologic effects in female rats included reduced red blood cell counts and hemoglob in concentrations at ≥ 82 mg/kg/ day and increased reticulocytes, decreased platelets, and increased bone marrow cellularity at 304 mg/kg/ day

. L iver effects including cytoplasmic alterations, hepatocellular degeneration, and pigmentation were reported in the mid

- and high

- dose groups ( ≥ 129 mg/kg/ da y for males and ≥ 151 mg/kg/ day for females; statistics not reported). Additionally, c ytoplasmic al terations of liver hepatocytes , were observed in the lowest

- dose groups (69 mg/kg/ day for males and 82 mg/kg/ day for females). The lack of cytoplasmic granularity of the hepatocytes indicates that this response was not due to enzyme induction ( Greaves 2000 ). NTP (1993) identified a LOAEL for rats of 750 ppm (approximately 58.6 mg/kg/ day calculated using
water con sumption rates and body weights measured during the last week of exposure and, therefore, slightly different from those reported by the study authors (U.S. EPA 2010) ) based on decreased red blood cell count and hemoglobin in female rats. A NOAEL was not identified.

A reduction in body weight gain at ≥ 3,000 ppm was observed in male and female mice. An increase in relative kidney weight was also observed at all doses i n female mice. Body weight reductions followed decreased water consumption

. No histopathologic changes were noted at any dose level, however, relative kidney weights showed a statistically significant increase at 750 and 1,500 ppm in the absence of reduction in body weight gain. NTP (1993) identified a LOAEL for mice of 3,000 ppm (approximately 553

– 676 mg/kg/ day calculated using water consumpt ion rates and body weights measured during the last week of exposure and, therefore, slightly different from those reported by the study authors (U.S. EPA 2010) ) based on reduced body weight and body weight gain.7

Dodd et al. (1983) conducted a 90

- day subchronic inhalation study using F344 rats (16/gender/group) exposed to EGBE for 6 hours/day, 5 days/week at concentrations of 0, 5, 25, and 77 ppm . After 6 weeks , the 77 ppm female rats had statistically significant decreases in red blood cell co unts (13%) and hemoglobin concentrations, accompanied by an 11% increase in mean corpuscular hemoglobin

. The authors reported a LOAEL of 77 ppm ( approximately 70

– 75 mg/kg/ day using the species

- specific sub chronic reference values for inhalation rate and body weight from U.S. EPA 1988) based on decreases in red blood cell count and hemoglobin concentrations, accompanied by an increase in mean corpuscular hemoglobin in both genders

.
NTP (2000) conducted a subchronic study in F344 rats and B6C3F1 mice (10/gender)

. Rats and mice were exposed to EGBE concentrations of 0, 31, 62.5, 125, 250, and 500 ppm (0, 150, 302, 604, 1,208, and 2,416 mg/m3) 6 hours/day, 5 days/week for 14 weeks. NTP (2000) identified a LOAEL of 31 ppm (app roximately 30 mg/kg/ day using the species

- specific sub chronic reference values for inhalation rate and body weight from U.S. EPA 1988) in female rats based on decreases in hematocrit, hemoglobin, and red blood cell count and a LOAEL of 62.5 ppm (approximately 57 mg/kg/ day using the species

- specific sub chronic reference values for inhalation rate and body weight from U.S. EPA 1988) in male rats based on a decrease in red blood cell count

. Histopathologic effects were observed in male and female ra ts. Effects reported in female rats included liver necrosis at 250 ppm and centrilobular degeneration and renal tubular degeneration at 500 ppm (approximately 243 and 486 mg/kg/ day, respectively, using the species

- specific subchronic reference values for inhalation rate and body weight from U.S. EPA 1988)

. Other effects reported in both genders included: excessive splenic congestion in the form of extramedullary hematopoiesis (at 250 ppm in male rats and 125 ppm in female rats ; approximately 227 and 121 mg /kg/ day, respectively, using the species

- specific subchronic reference values for inhalation rate and body weight from U.S. EPA 1988) ), hemosiderin accumulation in Kupffer cells (at 125 ppm in male rats and 62.5 ppm in female rats ; approximately 113 and 61 mg/kg/ day, respectively, using the species

- specific subchronic reference values for inhalation rate and body weight from U.S. EPA 1988) ), intracytoplasmic hemoglobin (at 125 ppm in male rats and 31 ppm in female rats ; approximately 113 and 30 mg/kg/ day, r espectively, using the species

- specific subchronic reference values for inhalation rate and body weight from U.S. EPA 1988) ), hemosiderin deposition (at 125 ppm in male rats and 62.5 ppm in female rats ; approximately 113 and 61 mg/kg/ day, respectively, usi ng the species

- specific subchronic reference values for inhalation rate and body weight from U.S. EPA 1988) ), and bone marrow hyperplasia (at 250 ppm in male rats and 62.5 ppm in female rats ; approximately 227 and 61 mg/kg/ day, respectively, using the spec ies

- specific subchronic reference values for inhalation rate and body weight from U.S. EPA 1988) ). For mice, the authors identified a LOAEL of 62.5 ppm (approximately 87

– 90 mg/kg/ day for male and female , respectively, using the species

- specific sub chronic reference values for inhalation rate and body weight from U.S. EPA 1988) based on histopathological changes in the forestomach ( including: necrosis, ulceration, inflammation, and epithelial hyperplasia) in both males and females. S igns consistent with the hemolytic effects of EGBE ( including: decreased red blood cell counts, increased reticulocyte counts, and increased mean corpuscular volume) were also observed at 250 and 500 ppm ( approximately 350

– 361 mg/kg/ day and 699

– 7218

mg/kg/ day in male s and female s , respectively , using the species

- specific sub chronic reference values for inhalation rate and body weight from U.S. EPA 1988) in male and female mice.

NTP (2000) also completed a 2

- year inhalation study of EGBE in both F344 rats and B6C3F1 mice. In this study, animals were exposed to EGBE for 6 hours/day, 5 days/week at concentrations of 0, 31, 62.5, and 125 ppm (0, 150, 302, and 604 mg/m3) for groups of 50 F344/N rats and 0, 62.5, 125, and 250 ppm (0, 302, 604, and 1,208 mg/m3) for groups of 50 B6C3F1 mice. The authors identified a LOAEL of 31 ppm (approximately 28 mg/kg/ day using the spe cies

- specific chronic reference values for inhalation rate and body weight from U.S. EPA 1988) in rats based on decreases in hematocrit, hemoglobin, and red blood cell count in female rats in a satellite group observed at 3 and 6 months

. The authors identified 62.5 ppm (approximately 91 mg/kg/ day using the spe cies

- specific chronic reference values for inhalation rate and bod y weight from U.S. EPA 1988) as the LOAEL for mice based on hemosiderin deposition.

One long

- term occupational study of EGBE was identified in the literature. Haufroid et al. (1997) reported a small decrease in hematocrit and increase in mean corpuscular hemoglobin in a cross sectional study of 31 workers exposed to an average concentration of 0.6 ppm EGBE over 1 to 6 years. The biological significance of these findings, however, is unclear as they were within normal clinical ranges and no other measured parameters were affected by EGBE exposure.
Conclusions Regarding Human Hazard Potential

There is evidence to in dicate that the human red blood cell response to EGBE exposure is less than that of rodents, h owever, this conclusion is based on a relatively small number of in vitro and short

- term human exposure studies with supporting evidence from pharmacokinetic models (Bartnik et al. 1987; Udden 2000; 2002; Carpenter et al. 1956 ; Corley et al. 1994; 1997) . Little is known of the long

- term or repeated exposure responses in humans to EGBE.

In 20 10, EPA concluded in the IRIS toxicological review of EGBE that human red blood cells do appear capable of responding similarly to the causative EGBE metabolites, albeit at much higher exposures (U.S. EPA 2010). The IRIS toxicological review of EGBE employ ed an interspecies uncertainty factor of 1 to derive the reference values for EGBE in part because there was not a preponderance of toxicodynamic data in both animals and humans describing why humans are less sensitive than rats to the hematologic effects in question (U.S. EPA 2010). Also, EPA calculated a human equivalent concentration LOAEL (LOAEL HEC ) for hematologic effects of 271 mg/m 3 (approximately 77 mg/kg/ day, assuming constant exposure, an inhalation rate of 20

m 3 /day , and a 70 kg human) u sing pharmacokinetic model estimates (Corley 1994; 1997) of the human internal dose equivalent of the toxic metabolite BAA to that estimated for female rats exposed to 31 ppm EGBE in the NTP (2000) study (U.S. EPA 2010). In its assessment of EGBE, the Euro pean Union carried out a slightly different calculation based on the same underlying data9

and reported a similar, but slightly higher, human equivalent LOAEL of 474 mg/m 3 (approximately 135 mg/kg/ day) (E.U. 2006).
Additionally, multiple animal studies by the NTP reported liver toxicity (e.g., cytoplasmic alterations of liver hepatocytes at 750 ppm (approximately 69 mg/kg/day) in male rats and 750 ppm (82 mg/kg/day) in female rats ( NTP 1993 ) and liver necrosis at 250 ppm (approximately 243 mg/kg/day) in female rats ( NTP 2000 )) to which humans do not demo nstrate decreased sensitivity. These findings provide further evidence of EGBE’s potential toxicity to humans at moderately low to low doses.

Therefore, the available evidence is sufficient to conclude tha t EGBE can be reasonably anticipated to demonstrate moderately high to high chronic toxicity in humans based on the EPCRA Section 313 listing criteria

.

References
Bartnik FG; Reddy AK; Klecak G; Zimmermann V; Hostynek JJ; Kunstler K (1987). Percutaneous absorption, metabolism, and hemolytic activity of n

- butoxyethanol. Fundam Appl Toxicol, 8: 59

- 70.
Bauer P; Weber M; Mur JM; Protois JC; Bollaert PE; Condi A; Larcan A; Lambert H (1992). Transient

non

- cardiogenic pulmonary edema following massive ingestion of ethylene glycol butyl ether. Intensive Care Med, 18: 250

- 251.
Burkhart KK; Donovan JW (1998). Hemodialysis following butoxyethanol ingestion. Clin Toxicol, 36: 723

- 725.
Carpenter CP; Pozzani UC; Weil CS; Nair JH III; Keck GA; Smyth HF Jr (1956). The toxicity of butyl cellosolve solvent. AMA Arch Ind Health, 14: 114

- 131.
Chiewchanwit T; Au WW (1995). Mutagenicity and cytotoxicity of 2

- butoxyethanol and its metabolite, 2

- butoxyacetaldehyde, in Chinese hamster ovary (CHO

- AS52) cells. Mutat Res, 334: 341

- 346.
Commonwealth of Australia (1996). National Industrial Chemicals Notification and Assessment Scheme (NICNAS)

- priority existing chemical no. 6

- 2

- butoxyethanol in cleaning products. Australian Government Publishing Service. Canberra, Australia

. http://www.nicnas.gov.au/__data/assets/pdf_file/0003/4368/PEC_6_2

- Butoxyethanol

- in

- Cleaning

Products_Full_Report_PDF.pdf

. Corley RA; Bormett GA; Ghanayem BI (1994). Physiologically

- based pharmacokinetics of 2

- butoxyethanol and its major metabolite 2

- butoxyacetic acid, in rats and humans. Toxicol Appl Pharmacol, 129: 61

- 79.
Corley RA; Grant DM; Farris E; Weitz KK; Soelberg JJ ; Thrall KD; Poet TS (2005). Determination of age and gender differences in biochemical processes affecting the disposition of 2

- butoxyethanol and its metabolites in mice and rats to improve PBPK modeling. Toxicol Lett, 156: 127

- 161.
Corley RA; Markham DA; Banks C; Delorme P; Masterman A; Houle JM (1997). Physiologically based pharmacokinetics and the dermal absorption of 2

- butoxyethanol vapor by humans. Fundam Appl Toxicol, 39: 120

- 130.10

Corley RA; Weitz KK; Mast TJ; Miller RA; Thrall BD (1999). Short

- term studies to evaluate the dosimetry and modes of action of EGBE in B6C3F1 mice [final report]. Battelle Memorial Institute. Richland, WA. Battelle Project No. 29753.
Dean BS; Krenzelok EP (1991). Critical evaluation of pediatric ethylene glycol monobutyl eth er poisonings. Vet Hum Toxicol, 33: 362.
Dill JA; Lee KM; Bates DJ; Anderson DJ; Johnson RE; Chou BJ; Burka LT; Roycroft JH (1998). Toxicokinetics of inhaled 2

- butoxyethanol and its major metabolite, 2

- butoxyacetic acid, in F344 rats and B6C3F1 mice. Toxic ol Appl Pharmacol, 153: 227

- 242.
Dodd DE; Snellings WM; Maronpot RR; Ballantyne B (1983). Ethylene glycol monobutyl ether: acute, 9

- day, and 90

- day vapor inhalation studies in Fischer 344 rats. Toxicol Appl Pharmacol, 68: 405

- 414.
Doe JE (1984). Further st udies on the toxicology of the glycol ethers with emphasis on rapid screening and hazard assessment. Environ Health Perspect, 57: 199

- 206.
ECETOC (1994). Butoxyethanol criteria document. Special Report No. 7. European Centre for Ecotoxicology and Toxicolog y of Chemicals. Brussels, Belgium.
Elias Z; Daniere MC; Marande AM; Poirot O; Terzetti F; Schneider O (1996). Genotoxic and/or epigenetic effects of some glycol ethers: Results of different short

- term tests. Occup Hyg, 2: 187

- 212
E.U. (2006). European Union Risk Assessment Report: 2

- butoxyethanol. http://echa.europa.eu/documents/10162/e74a38e1

- b9e1

- 4568

- 92c5

- 615c4b56f92d

. Exon JH; Mather GG; Bussiere JL; Olson DP; Talcott PA (1991). Effects of subchronic exposure of rats to 2

- methoxyethanol or 2

- butoxyethanol: thymic atrophy and immunotoxicity. Fundam Appl Toxicol, 16: 830

- 840.

Ezov N; Levin

- Harrus T; Mittelman M; Redlich M; Shabat S; Ward SM; Peddada S; Nyska M; Yedgar S; Nyska A (2002). A chemically induced rat model of hemolysis with disseminated thrombosis. Cardiovasc Toxicol, 2: 181

- 194.
Foster PM; Lloyd SC; Blackburn DM (1987). Comparison of the in vivo and in vitro testicular effects produced by met hoxy

- , ethoxy

- and N

- butoxy acetic acids in the rat. Toxicology, 43: 17

- 30.
Ghanayem BI; Blair PC; Thompson MB; Maronpot RR; Matthews HB (1987). Effect of age on the toxicity and metabolism of ethylene glycol monobutyl ether (2

- butoxyethanol) in rats. Toxi col Appl Pharmacol, 91: 222

- 234.
Ghanayem BI; Sanchez IM; Matthews HB (1992). Development of tolerance to 2

- butoxyethanol

- induced hemolytic anemia and studies to elucidate the underlying mechanisms. Toxicol Appl Pharmacol, 112: 198

- 206.
Ghanayem BI; Sulliv an CA (1993). Assessment of the haemolytic activity of 2

- butoxyethanol and its major metabolite, butoxyacetic acid, in various mammals including humans. Hum Exp Toxicol, 12: 305

- 311.
Gijsenbergh FP; Jenco M; Veulemans H; Groeseneken D; Verberckmoes R; Delo oz HH (1989). Acute butylglycol intoxication: a case report. Hum Toxicol, 8: 243

- 245.11

Gingell R; Boatman RJ; Lewis S (1998). Acute toxicity of ethylene glycol mono

- n

- butyl ether in the guinea pig. Food Chem Toxicol, 36: 825

- 829.
Gollapudi BB; Barber ED; La wlor TE; Lewis SA (1996). Re

- examination of the mutagenicity of ethylene glycol monobutyl ether to Salmonella tester strain TA97a. Mutat Res, 370: 61

- 64.
Grant D; Sulsh S; Jones HB; Gangolli SD; Butler WH (1985). Acute toxicity and recovery in the hemopoie tic system of rats after treatment with ethylene glycol monomethyl and monobutyl ethers. Toxicol Appl Pharmacol, 77: 187

- 200.
Greaves P (2000). Hepatocellular hypertrophy and hyperplasia. In Histopathology of preclinical toxicity studies: interpretation an d relevance in drug safety evaluation (pp. 445

- 448). New York, NY: Elsevier

. Green T; Toghill A; Lee R; Moore R; Foster J (2002). The development of forestomach tumors in the mouse following exposure to 2

- butoxyethanol by inhalation Studies on the mode of action and relevance to humans. Toxicology, 180: 257

- 273.
Gualtieri JF; DeBoer L; Harris CR; Corley R (2003). Repeated ingestion of 2

- butoxyethanol: case report and literature review. J Toxicol Clin Toxicol, 41: 57

- 62.
Gualtieri JF; Harris CR; Roy R; Corley RA; Manderfield C (1995). Multiple 2

- butoxyethanol intoxications in the same patient: Clinical findings, pharmacokinetics, and therapy. J Toxicol Clin Toxicol, 33: 550

- 551.
Hardin BD; Goad PT; Burg JR (1984). Developmental toxicity of four glycol et hers applied cutaneously to rats. Environ Health Perspect, 57: 69

- 74.

Haufroid V; Thirion F; Mertens P; Buchet J

- P; Lison D (1997). Biological monitoring of workers exposed to low levels of 2

- butoxyethanol. Int Arch Occup Environ Health, 70: 232

- 236.

Heind el JJ; Gulati DK; Russell VS; Reel JR; Lawton AD; Lamb JC IV (1990). Assessment of ethylene glycol monobutyl and monophenyl ether reproductive toxicity using a continuous breeding protocol in Swiss CD

- 1 Mice. Fundam Appl Toxicol, 15: 683

- 696.

Hoflack JC; L ambolez L; Elias Z; Vasseur P (1995). Mutagenicity of ethylene glycol ethers and of their metabolites in Salmonella typhimurium his. Mutat Res, 341: 281

- 287.
Jacobs GA; Martens MA (1989). An objective method for the evaluation of eye irritation in vivo. Fo od Chem Toxicol, 27: 255

- 258.
Johanson G (1986). Physiologically based pharmacokinetic modeling of inhaled 2

- butoxyethanol in man. Toxicol Lett, 34: 23

- 31.
Johanson G; Boman A; Dynesius B (1988). Percutaneous absorption of 2

- butoxyethanol in man. Scand J Work Environ Health, 14: 101

- 109.
Johanson G; Boman A (1991). Percutaneous absorption of 2

- butoxyethanol vapour in human subjects. Occup Environ Med, 48: 788

- 792.
Johanson G; Johnsson S (1991). Gas chromatographic determination of butoxyacetic acid in huma n blood after exposure to 2

- butoxyethanol. Arch Toxicol, 65: 433

- 435.12

Keith G; Coulais C; Edorh A; Bottin MC; Rihn B (1996). Ethylene glycol monobutyl ether has neither epigenetic nor genotoxic effects in acute treated rats and in subchronic treated v

- HA

- r as transgenic mice. Occup Hyg, 2: 237

- 249.
Kennah HE II; Hignet S; Laux PE; Dorko JD; Barrow CS (1989). An objective procedure for quantitating eye irritation based upon changes of corneal thickness. Fundam Appl Toxicol, 12: 258

- 268.
Klaunig JE; Kamendulis LM (2005). Mode of action of butoxyethanol

- induced mouse liver hemangiosarcomas and hepatocellular carcinomas. Toxicol Lett, 156: 107

- 115.
Koshkaryev A; Barshtein G; Nyska A; Ezov N; Levin

- Harrus T; Shabat S; Nyska M; Redlich M; Tsipis F; Yedgar S (2003). 2

- Butoxyethanol enhances the adherence of red blood cells. Arch Toxicol, 77: 465

- 469.
Kumagai S; Oda H; Matsunaga I; Kosaka H; Akasaka S (1999). Uptake of 10 polar organic solvents during short

- term respiration. Toxicol Sci, 48: 255

- 263.
Laitinen J (1998 ). Correspondence between occupational exposure limit and biological action level values for alkoxyethanols and their acetates. Int Arch Occup Environ Health, 71: 117

- 124.
Lee KM; Dill JA; Chou BJ; Roycroft JH (1998). Physiologically based pharmacokinetic model for chronic inhalation of 2

- butoxyethanol. Toxicol Appl Pharmacol, 153: 211

- 226.
Medinsky MA; Singh G; Bechtold WE; Bond JA; Sabourin PJ; Birnbaum LS; Henderson RF (1990). Disposition of three glycol ethers administered in drinking water to male F344 /N rats. Toxicol Appl Pharmacol, 102: 443

- 455.
Nagan o K; Nakayama E; Koyano M; Oobayash i H; Adachi H; Yamada T (1979). Testicular atrophy of mice induced by ethylene glycol mono alkyl ethers (author's translation). Sangyo Igaku/Jap. J. Ind. Health. 21: 29

- 35.
Nagano K; Nakayama E; Oobayashi H; Nishizawa T; Okuda H; Yamazaki K (1984). Experimental studies on toxicity of ethylene glycol alkyl ethers in Japan. Environ Health Perspect, 57: 75

- 84.
Nelson BK; Setzer JV; Brightwell WS; Mathinos PR; Kuczuk MH; Wea ver TE; Goad PT (1984). Comparative inhalation teratogenicity of four glycol ether solvents and an amino derivative in rats. Environ Health Perspect, 57: 261

- 271.
NTP (1993). NTP technical report on toxicity studies of ethylene glycol ethers: 2

- methoxyetha nol, 2

- ethoxyethanol, 2

- butoxyethanol (CAS Nos 109

- 86

- 4, 110

- 80

- 5, 111

- 76

- 2) administered in drinking water to F344/N rats and B6C3F1 mice. National Toxicology Program. Research Triangle Park, NC. 26; NIH Publication 93

- 3349.
NTP (1996). Toxicology and car cinogenesis studies of acetonitrile (CAS No 75

- 05

- 8) in F344/N rats and B6C3F1 mice (inhalation studies). National Toxicology Program. Research Triangle Park, NC.http://ehp.niehs.nih.gov/ntp/docs/400 4xx doc.html.
NTP (2000). NTP technical report on the to xicology and carcinogenesis studies of 2 butoxyethanol (CAS No. 111

- 76

- 2) in F344/N rats and B6C3F1 mice (inhalation studies). National Toxicology Program. Research Triangle Park, NC. NTP TR 484. http://ntp.niehs.nih.gov/?objectid=070AC403

- B110

- CA79

- 3A23AF79DE7B752A

.13

Osterhoudt KC (2002). Fomepizole therapy for pediatric butoxyethanol intoxication. J Toxicol Clin Toxicol, 40: 929

- 930.
Poet TS; Soelberg JJ; Weitz KK; Mast TJ; Miller RA; Thrall BD; Corley RA (2003). Mode of action and pharmacokinetic studies of 2

- butoxyethanol in the mouse with an emphasis on forestomach dosimetry. Toxicol Sci, 71: 176

- 189.
Rambourg

- Schepens MO; Buffet M; Bertault R; Jaussaud M; Journe B; Fa y R; Lamiable D (1988). Severe ethylene glycol butyl ether poisoning. Kinetics and metabolic pattern. Hum Toxicol, 7: 187

- 189.
Redlich M; Maly A; Aframian D; Shabat S; Ezov N; Levin

- Harrus T; Nyska M; Nyska A (2004). Histopathologic changes in dental and o ral soft tissues in 2

- butoxyethanol

- induced hemolysis and thrombosis in rats*. J Oral Pathol Med, 33: 424

- 429.
Rettenmeier AW; Hennigs R; Wodarz R (1993). Determination of butoxyacetic acid and N

- butoxyacetyl

glutamine in urine of lacquerers exposed to 2

- butoxyethanol. Int Arch Occup Environ Health, 65: S151

- S153.
Sabourin PJ; Medinsky MA; Birnbaum LS; Griffith WC; Henderson RF (1992). Effect of exposure concentration on the disposition of inhaled butoxyethanol by F344 rats. Toxicol Appl Pharmacol, 114: 232

- 238.
Sabourin PJ; Medinsky MA; Thurmond F; Birnbaum LS; Henderson RF (1993). Erratum to: Effect of dose on the disposition of methoxyethanol, ethoxyethanol, adn butoxyethanol administered dermally to male F344/N rats. Fundamental and Applied Toxicology 19:124

- 132. Fundam Appl Toxicol, 20: 508

- 510.
Shabat S; Nyska A; Long PH; Goelman G; Abramovitch R; Ezov N; Levin

- Harrus T; Peddada S; Redlich M; Yedgar S; Nyska M (2004). Osteonecrosis in a chemically induced rat model of human hemolytic disorders associ ated with thrombosis

-- a new model for avascular necrosis of bone. Calcif Tissue Int, 74: 220

- 228.
Shepard KP (1994). Ethylene glycol monobutyl ether: Acute oral toxicity study in the guinea pig. Eastman Kodak Company for Chemical Manufacturers Association. Rochester, NY and Arlington, VA.
Shyr LJ; Sabourin PJ; Medinsky MA; Birnbaum LS; Henderson RF (1993). Physiologically based modeling of 2

- butoxyethanol disposition in rats following different routes of exposure. Environ Res, 63: 202

- 218.
Tyl RW; Millicovs ky G; Dodd DE; Pritts IM; France KA; Fisher LC (1984). Teratologic evaluation of ethylene glycol monobutyl ether in Fischer 344 rats and New Zealand white rabbits following inhalation exposure. Environ Health Perspect, 57: 47

- 68.
Tyler TR (1984). Acute and subchronic toxicity of ethylene glycol monobutyl ether. Environ Health Perspect, 57: 185

- 191.
U.S. EPA (1988). Recommendations for and Documentation of Biological Values for Use in Risk Assessment. U.S. Environmental Protection Agency. Washington, D.C. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=34855#Download

.14

U.S. EPA (2005). Guidelines for carcinogen risk assessment, Final Report. Risk Assessment Forum, U.S. Environmental Protection Agency. Washington, DC. EPA/630/P

- 03/001F. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=116283

. U.S. EPA (2010). Toxicological review of Ethylene Gly col Monobutyl Ether (CASRN 111

- 76

- 2 ) in support of summary information on the Integrated Risk Information System (IRIS). U.S. Environmental Protection Agency. Washington, D.C. http://www.epa.gov /iris/toxreviews/0500tr.pdf

Udden MM (2000). Rat erythrocyte morphological changes after gavage dosing with 2

- butoxyethanol: a comparison with the in vitro effects of butoxyacetic acid on rat and human erythrocytes. J Appl Toxicol, 20: 381

- 387.
Udden MM ( 2002). In vitro sub

- hemolytic effects of butoxyacetic acid on human and rat erythrocytes. Toxicol Sci, 69: 258

- 264.
Wier PJ; Lewis SC; Traul KA (1987). A comparison of developmental toxicity evident at term to postnatal growth and survival using ethylene g lycol monoethyl ether, ethylene glycol monobutyl ether, and ethanol. Teratog Carcinog Mutagen, 7: 55

- 64.

Zeiger E; Anderson B; Haworth S; Lawlor T; Mortelmans K (1992). Salmonella mutagenicity tests: V Results from the testing of 311 chemicals. Environ Mol Mutagen, 19: 2

- 141.