Ethylene glycol butyl ether (EGBE) is a versatile chemical that has been used in a variety of applications for more than 50 years. It is a particularly effective solvent because it can be used with both water-based and oil-based systems.

EGBE has also been extensively studied to determine its toxicity. Governments and independent expert groups have used that data to establish exposure levels below which no risk is expected.

The Environmental Protection Agency (EPA), on November 18, 2004, after extensive review of the compound's toxicity and exposure data, removed EGBE from its list of Hazardous Air Pollutants (HAPs) (Federal Register Vol.69 No.228, Nov.29, 2004). In announcing the decision, EPA Deputy Assistant Administrator Brenner said that delisting EGBE "will create an incentive for industry to use less toxic and less environmentally harmful compounds and focus on the pollutants that are really the most dangerous."

Recent Expert Reviews of EGBE Toxicity

EPA has several times in the past three years reviewed EGBE. The Agency adopted a Reference Concentration (RfC) for EGBE in 1999. That RfC of 13 mg/cubic meter is a level at which no appreciable risk is expected with lifetime exposure, even for susceptible individuals. EPA's review found that EGBE is neither a primary reproductive nor developmental toxicant, nor, because EPA concluded it is not mutagenic, it is not likely to cause cancer in humans. EPA found the most sensitive endpoint in rodents is hemolysis, an effect to which human red blood cells are much more resistant. The Agency used a physiologically based pharmacokinetic (PBPK) model for EGBE that has shown that human exposure high enough to cause hemolysis (effects on red blood cells) is not expected to occur in humans under any normal exposure conditions.

After that initial EPA review, a lifetime study of EGBE in mice and rats was completed by the U.S. National Toxicology Program (NTP). Although that study resulted in some excess tumors, the study itself and panel-sponsored research subsequent to the NTP study have demonstrated that the mechanisms by which these tumors were caused are unlikely to be relevant to humans.

The Agency reaffirmed its 13 mg/cubic meter RfC in removing EGBE from its list of HAPs (see more below) in November 2004. As that decision said, the Agency's recent reviews included its interpretation of the NTP study and conclusion that extensive data show that its 1999 RfC is "sufficient" to prevent any cancer risk to humans. EPA concluded that the tumors in mice were caused by mechanisms that are not relevant to human risk. See: EPA docket OAR-2003-0188 Document 0028 (http://docket.epa.gov/edkpub/index.jsp). In May 2004, an outside expert panel appointed by the Agency agreed with EPA's interpretation of the NTP study.

In June 2004, the World Health Organization's International Agency for Research on Cancer (IARC) also evaluated the NTP study and several other EGBE studies. That Agency's expert panel concluded that EGBE is not classifiable as to human cancer because there is inadequate evidence in humans and limited evidence in animals. That finding parallels EPA's conclusion that the tumors found in lifetime animal studies of EGBE are not relevant to humans. As both EPA and IARC noted, these conclusions are supported by extensive experimental work on EGBE sponsored by the Panel that was conducted at the Indiana University Medical Center and the Pacific Northwest National Laboratory.

EPA's Delisting of EGBE

On November 18, 2004, EPA removed EGBE from the Clean Air Act (CAA) list of HAPs. EGBE is thus no longer subject to Maximum Achievable Control Technology (MACT), residual risk, and other specific requirements found in the CAA.

EPA's decision to delist EGBE means that many companies that use EGBE in product formulation can do so without being subject to requirements considered inappropriate for this chemical. In announcing its decision, EPA said: "This action creates incentives for industry to use EGBE instead of other more toxic solvents." Like most solvents, EGBE continues to be regulated as a volatile organic compound (VOC) and thus its emissions must be reported on the Toxics Release Inventory.

EPA's announcement, Fact Sheet, Final Rule Federal Register, and related documents finding the NTP mouse tumors not relevant to man are available at: http://www.epa.gov/airlinks/airlinks3.html.

EPA is directed under the CAA to delist HAPs if there are "adequate data on the health and environmental effects of the substance to determine that emissions, ambient concentrations, bioaccumulation or deposition of the substance may not reasonably be anticipated to cause any adverse effects to human health or adverse environmental effects." CAA Section 112(b)(3)(C).

Applying this standard, said the Agency: "After extensively reviewing the levels of EGBE in the air Americans breathe and the health and environmental impacts associated with those levels, EPA has concluded that potential outdoor exposures to EGBE may not reasonably be anticipated to cause human health or environmental problems."

In its proposed rule, EPA had found wide margins of safety ("Hazard Quotients") between estimated maximum exposures and lowest toxicity effect levels. The Agency found maximum human exposures would be 16 to 50 times lower than the lowest level expected to pose any risk to human health. Thus, EPA concluded: "[W]e judge that the potential for human health and environmental effects [from EGBE] is sufficiently low to provide reasonable assurance that such adverse effects will not occur." See: 68 Fed. Reg. 65648 (Nov. 21, 2003).

The Glycol Ether Panel filed the EGBE petition in August 1997. EPA issued its proposed rule on November 21, 2003. The Agency received 15 favorable comments. Only three short comments, which according to EPA contained no substantive information, opposed delisting.

The delisting of EGBE corrects an over-inclusive listing of HAPs by Congress more than a decade ago. In the early 1980's, animal studies on the lowest molecular weight ethylene glycol ethers (EGME and EGEE and their acetates) raised issues about their potential reproductive and developmental toxicity. Subsequent animal studies showed that EGBE does not cause such toxicity. Nonetheless, those issues about EGME and EGEE caused a category of all ethylene glycol ethers to be included when Congress listed as HAPs 189 chemicals in the 1990 CAA Amendments.

As noted above, EPA reviewed the lifetime rodent studies conducted in the 1990's by the NTP. The Agency's Delisting Fact Sheet says the reviews by Agency scientists and a peer review panel concluded: "[H]umans do not exhibit the cell changes that lead to the EGBE-related types of tumors seen in mice. Without these cell changes, tumors do not occur." Thus, says the Agency: "EPA concluded that humans cannot reasonably be anticipated to develop tumors from environmental concentrations of EGBE."

Other Expert Reviews of EGBE

Other governments and independent expert groups have reviewed the EGBE database.

Agreeing with EPA that the tumors in the NTP study were due to mechanisms not relevant to man, the European Union (EU) expert committee on chemical labeling has determined that EGBE does not pose risks of cancer for which warning labels are appropriate. The EU is currently conducting a risk assessment on EGBE and its acetate. This is expected to be complete in 2005.

The Cosmetics Ingredient Review (CIR) Expert Advisory Panel reaffirmed their 1996 review in 2002 that EGBE is "safe in hair and nail products at concentrations up to 10.0%." Like the EU and EPA, the CIR reviewed the NTP study and found it not relevant to human risk.

Only the Canadian Ministry of Health is known to have found rodent tumors in the NTP study of EGBE possibly relevant to humans. In 2003, Canada raised questions about the relevance of the mouse tumors. The Canadian assessment is at: www.ec.gc.ca/cceb1/eng/public/glyclos_e.html

EGBE in the Environment

EGBE's characteristics when released to land, water or air have also been studied, as have potential effects on the environment (Staples, C.A., et al. Ethylene Glycol Ethers: An Environmental Risk Assessment. Chemosphere 36(7), 1585-1613 (1998)).

EGBE moves to water because of its high solubility, low volatility and minimal tendency to bind to soil or sediment. In water, it will degrade rapidly — its half-life is shown as less than two weeks. Studies using a variety of protocols have found EGBE meets the U.S. EPA definition of "readily" biodegradable in both aerobic surface waters and under typical waste treatment plant conditions. In the air, EGBE has been shown to have a half-life of less than two days.

EGBE has been found to cause toxicity in fish and other organisms only at the high concentrations. These concentrations are high enough so that EGBE can be classified in U.S. EPA's "practically non-toxic" category. Tests with algae, yeast, protozoa, bacteria and fungi also provide evidence that EGBE would not be expected to cause adverse environmental effects except at concentrations well above any that have been found in the environment. The Canadian Government in 2003 found that EGBE would not cause harmful effects on the environment.

EPA's review and decision removing EGBE from the CAA list of HAPs also found EGBE emission unlikely to cause any adverse effects on the environment.

Occupational Exposure Limits (2004 Values for EGBE)

Advisory and regulatory groups around the world have established occupational exposure limits for EGBE and cautioned against skin contact. Some groups' limits are provided below. Consult listed groups for further information on these limit values.

American Conference of Governmental Industrial Hygienists (ACGIH TLV, USA)
 20 ppm
 97 mg/m3
 
Permissible Exposure Limit (OSHA - PEL, USA)
 50 ppm
 242 mg/m3
 
Indicative Limit Value (ILV - EU)
 20 ppm
 97 mg/m3
 
Maximale Arbeitsplatz-Konzentration (MAK- Germany)
 20 ppm
 97 mg/m3
 
Occupational Exposure Standard (OES - UK)
 20 ppm
 121 mg/m3
 
EGBE air concentrations measured in a number of workplaces show levels are typically well below these limits.

For further information on EGBE toxicity, refer to the following documents:

Boatman RJ and Knaak JB, Patty's Toxicology, Chapter 86 John Wiley and Sons (2001); and Boatman RJ. Corley RA, Green T, Klaunig JE and Udden MM, Review of the Tumorogenicity of 2-Butoxethanol in B6C3F1 Mice and its Relevance for Human Risk Assessment, J. Tox. Env. Health, Part B, 7:385-398 (2004).

This document summarizes information from the technical, scientific literature and is intended for reference by medical, scientific and regulatory personnel. The Ethylene and Propylene Glycol Ethers Panel of the American Chemistry Council and its member companies believe that this document is, as of the date of its publication, a technically accurate summary of available scientific information. However, the Panel and its member companies do not make any warranties, express or implied, regarding the completeness or accuracy of the information presented and assume no responsibility or liability for its use. New information may be developed subsequent to the publication of this summary, which may render the summary incomplete or inaccurate. The Panel and its member companies assume no responsibility to amend, revise, retract, or update the summary to reflect any such information that may become available after its publication.

June 2005

This information is brought to you by the member companies of the American Chemistry Council Ethylene and Propylene Glycol Ethers (EGE/PGE) Panel: Arch Chemicals Inc., The Dow Chemical Company, Eastman Chemical Company, Equistar Chemicals, LP, and Lyondell Chemical Company.

Ethylene glycol ethers are a group of chemicals with a wide variety of uses. Primary uses include solvents in paints, cleaners and inks. Some ethylene glycol ethers are recommended for use only in industrial applications; others have wide use in industrial, commercial and consumer applications.

All the commercially marketed ethylene glycol ethers have been tested in animal studies to assess potential toxicity to humans. Summaries of toxicity studies of ethylene glycol ethers conducted by numerous government, academic and industry researchers are available in Patty's Industrial Hygiene and Toxicology, Fifth Edition, Volume 7, Chapter 86 (2001) and in ECETOC Technical Report No. 64, The Toxicology of Glycol Ethers and Its Relevance to Man (2005). These data have been used to develop recommendations for use.

Ethylene glycol ethers have received some media attention and are included on some government lists of hazardous substances because the smallest molecular weight ethylene glycol ethers were found to cause adverse male and female reproductive effects and birth defects in rodent studies. Those particular ethylene glycol ethers have not been used in consumer products in the United States for the past 20 years. Other glycol ethers have been tested similarly, have been found not to cause such effects, and are used in a wide variety of products.

ETHYLENE GLYCOL ETHERS INFORMATION UPDATE

The Environmental Characteristics
of Ethylene Glycol Butyl Ether (EGBE)

The available scientific data show that ethylene glycol butyl ether (EGBE), a widely used solvent for many applications, is not persistent in the environment, does not bioaccumulate, is practically non-toxic to aquatic organisms, and therefore causes little or no adverse environmental impact. These characteristics complement EGBE's other attributes: minimal if any potential for adverse effects on humans when recommended precautions are followed, and a unique ability to serve as a solvent for both polar and non-polar compounds.

Physical Properties

EGBE tends to remain dissolved in water because of its low volatility (vapor pressure between 0.6 and 0.88 mm Hg) and minimal tendency to bind to soil (log Kow of 0.81 to 0.83). When dissolved in water, EGBE will accumulate only negligibly in aquatic organisms (calculated bioconcentration factor of 2.5).

Degradation

EGBE does not persist in the environment. In air, it has a half-life of less than two days; in water, its half-life is less than two weeks. Studies using a variety of protocols classify EGBE as "readily" or "inherently" biodegradable in both aerobic surface waters and under typical waste treatment plant conditions.

Aquatic Toxicity

Results from tests with EGBE on aquatic organisms fall into EPA's "practically non-toxic" category. Acute toxicity tests in seven different fish have found all lethal concentrations (LC50's) to be at least 800 milligrams/liter (mg/L); tests with aquatic invertebrates found LC50's of at least 500 mg/L. Tests with algae, yeast, protozoa, bacteria and fungi also show that EGBE will not cause adverse effects except at very high concentrations.

Putting It All Together

Because of its physical properties, most EGBE released to the environment is reasonably expected to remain in the water column, where it will rapidly degrade. As a result, EGBE appears not to be persistent and its concentration in the environment is very unlikely ever to be high. Adverse effects upon fish or other aquatic organisms will thus be near to non-existent. Indeed, all reported levels of EGBE in the environment are below concentrations at which toxicity would occur. In sum, EGBE is a not persistent, not bioaccumulative, "practically non-toxic" — a solvent that thus offers desirable environmental attributes.

This document summarizes information from the technical, scientific literature and is intended for reference by medical, scientific and regulatory personnel. The Ethylene and Propylene Glycol Ethers Panel of the American Chemistry Council and its member companies believe that this document is, as of the date of its publication, a technically accurate summary of available scientific information. However, the Panel and its member companies do not make any warranties, express or implied, regarding the completeness or accuracy of the information presented and assume no responsibility or liability for its use. New information may be developed subsequent to the publication of this summary, which may render the summary incomplete or inaccurate. The Panel and its member companies assume no responsibility to amend, revise, retract, or update the summary to reflect any such information that may become available after its publication.

乙二醇單丁醚（EGBE）是一種用途廣泛的化學(xué)產(chǎn)品而且在各種領(lǐng)域使用了50多年。它是一種特效溶劑，既可以用在水基物質(zhì)中使用，也可以用于油基物質(zhì)。

對(duì)乙二醇單丁醚的毒性也進(jìn)行過(guò)大范圍的研究。政府和獨(dú)立組織都曾使用這些數(shù)據(jù)，來(lái)確定在低于這些數(shù)值的情況下，是沒(méi)有毒性的。

2004年11月18日，美國(guó)環(huán)境保護(hù)局（EPA）在對(duì)化合物的毒性和已經(jīng)公布的數(shù)據(jù)進(jìn)行了全面審查之后，宣布乙二醇單丁醚不再屬于有害空氣污染物（HAPs）名單（2004年11月29日，聯(lián)邦記錄第69卷）上的有害物質(zhì)。在宣布這一決定的時(shí)候，環(huán)境保護(hù)局助理副局長(zhǎng)勃倫納說(shuō)，將乙二醇單丁醚從有害污染物名單上刪除“不但給使用低毒性化合物和對(duì)環(huán)境危害較輕化合物的行業(yè)帶來(lái)了生機(jī)，也促使人們把注意力放到那些真正有毒性的化合物上。” 

目前專家對(duì)乙二醇單丁醚毒性的審查

環(huán)境保護(hù)局曾經(jīng)在過(guò)去三年中幾次對(duì)乙二醇單丁醚進(jìn)行審查。環(huán)保局在1999年就采用了一套針對(duì)乙二醇單丁醚的參照濃度（RfC）。該參照濃度設(shè)定為每立方米13毫克，這是預(yù)計(jì)對(duì)人終生無(wú)害的水平，即使是對(duì)容易過(guò)敏的人也同樣適用。環(huán)境保護(hù)局在審查中發(fā)現(xiàn)，乙二醇單丁醚既不是產(chǎn)生毒性的主要原因，也不是導(dǎo)致毒性擴(kuò)大的主要原因，同時(shí)因?yàn)榄h(huán)境保護(hù)局把它列為非誘導(dǎo)有機(jī)體產(chǎn)生突變的物質(zhì)，它似乎也不會(huì)引發(fā)人類的癌癥。環(huán)境保護(hù)局發(fā)現(xiàn)，在實(shí)驗(yàn)中大多數(shù)嚙齒動(dòng)物的明顯反應(yīng)是溶血現(xiàn)象，而由于人類的紅細(xì)胞抵抗力更強(qiáng)，這種效果在人類身上的影響不大。環(huán)保局使用了一個(gè)針對(duì)乙二醇單丁醚的生理代謝動(dòng)力學(xué)（PBPK）模型，顯示出對(duì)人類的紅細(xì)胞產(chǎn)生影響，引發(fā)溶血現(xiàn)象的劑量要大得多，而在正常狀態(tài)下不會(huì)達(dá)到那種劑量。 

在環(huán)境保護(hù)局的那些初步的審查以后，美國(guó)國(guó)家毒理學(xué)規(guī)劃處（NTP）也完成了乙二醇單丁醚在鼠科動(dòng)物身上進(jìn)行的壽命研究試驗(yàn)。雖然在試驗(yàn)中有些老鼠身上長(zhǎng)出了過(guò)多的腫瘤，這個(gè)實(shí)驗(yàn)以及后來(lái)國(guó)家毒理學(xué)規(guī)劃處進(jìn)行的輔助實(shí)驗(yàn)，全都證明導(dǎo)致腫瘤產(chǎn)生的機(jī)制，不可能在人類身上產(chǎn)生類似的效果。

環(huán)保局在2004年11月將乙二醇單丁醚從有害空氣污染物名單上取消的時(shí)候，重申了它的每立方米13毫克的參照濃度的有效性。有關(guān)有害空氣污染物名單的詳細(xì)情況，請(qǐng)看下文。正中該決定所說(shuō)的，環(huán)保局最近的審查包括了國(guó)家毒理學(xué)規(guī)劃處的說(shuō)明性實(shí)驗(yàn)，并得出結(jié)論說(shuō)，該局的1999年參照濃度對(duì)預(yù)防人類癌變的風(fēng)險(xiǎn)是“足夠的”。環(huán)境保護(hù)局推斷，在老鼠身上產(chǎn)生腫瘤的機(jī)制不會(huì)讓人類冒類似的風(fēng)險(xiǎn)。參看：環(huán)境保護(hù)局第0028號(hào)文件OAR-2003-0188號(hào)摘要（http：//docket.epa.gov/edkpub/index.jsp）。2004年5月，環(huán)保局委任的一個(gè)局外專家小組，也同意環(huán)境保護(hù)局對(duì)國(guó)家毒理學(xué)規(guī)劃處的研究結(jié)果進(jìn)行的說(shuō)明。

2004年6月，世界衛(wèi)生組織的國(guó)際腫瘤研究機(jī)構(gòu)（IARC）也評(píng)估了國(guó)家毒理學(xué)規(guī)劃處的研究結(jié)果，同時(shí)也對(duì)其它幾個(gè)針對(duì)乙二醇單丁醚的研究結(jié)果進(jìn)行了評(píng)估。該組織的專家小組得出結(jié)論，乙二醇單丁醚不應(yīng)劃分到導(dǎo)致人類癌變的類別，因?yàn)闆](méi)有充分的人身實(shí)驗(yàn)證據(jù)，在動(dòng)物身上得出的實(shí)驗(yàn)數(shù)據(jù)也很有限。這一結(jié)論，與環(huán)境保護(hù)局在動(dòng)物身上進(jìn)行乙二醇單丁醚壽命實(shí)驗(yàn)并發(fā)現(xiàn)腫瘤，并得出人類并不會(huì)因此發(fā)生癌變的結(jié)論桴鼓相應(yīng)。正如環(huán)境保護(hù)局和國(guó)際腫瘤研究機(jī)構(gòu)共同指出的那樣，這些結(jié)論的背后，有大范圍的乙二醇單丁醚實(shí)驗(yàn)相支持，這些實(shí)驗(yàn)都是由印第安納大學(xué)醫(yī)學(xué)中心和太平洋西北國(guó)家實(shí)驗(yàn)室主持的。

環(huán)境保護(hù)局對(duì)乙二醇單丁醚的除名

2004年11月18日，環(huán)境保護(hù)局將乙二醇單丁醚從《清潔空氣法》（CAA）規(guī)定的有害空氣污染物名單上除名。從此乙二醇單丁醚不再受《清潔空氣法》中規(guī)定的最大化控制技術(shù) （MACT）、殘余物風(fēng)險(xiǎn)和其它特別要求的限制。

環(huán)境保護(hù)局將乙二醇單丁醚除名的決定意味著許多在生產(chǎn)過(guò)程中使用乙二醇單丁醚的公司可以放開(kāi)手腳，不再受原來(lái)那些對(duì)這種化學(xué)產(chǎn)品的種種不當(dāng)要求的限制。在宣布這一決定的同時(shí)，環(huán)境保護(hù)局說(shuō)道：“這一行動(dòng)將為使用乙二醇單丁醚代替其它毒性較強(qiáng)的溶劑的行業(yè)帶來(lái)生機(jī)。”和許多溶劑一樣，乙二醇單丁醚還會(huì)被當(dāng)作揮發(fā)性有機(jī)化合物（VOC）進(jìn)行管理，它的排放必須由“有毒物質(zhì)排放清單”做出匯報(bào)。

環(huán)境保護(hù)局的公告、情況說(shuō)明書、最終法案聯(lián)邦公告、以及國(guó)家毒理學(xué)規(guī)劃處老鼠腫瘤對(duì)人類沒(méi)有影響的有關(guān)報(bào)告可以在以下網(wǎng)頁(yè)中找到：http://www.caa.gov/airlinks/airlinks3.html。

環(huán)境保護(hù)局得到指示，根據(jù)《清潔空氣法》將有關(guān)物質(zhì)從有害空氣污染物名單上除名，只要該物質(zhì)“有足夠的對(duì)健康和環(huán)境產(chǎn)生的影響的數(shù)據(jù)證明，該物質(zhì)的排放、在周圍環(huán)境中的集結(jié)、在生物體內(nèi)的積累或者沉積不會(huì)對(duì)損害人體健康或者對(duì)環(huán)境帶來(lái)不良影響。”《清潔空氣法》第112條（b）（3）（C）款。

在執(zhí)行這條標(biāo)準(zhǔn)的過(guò)程中，環(huán)保局宣布：“在對(duì)美國(guó)居民呼吸的空氣中各種濃度的乙二醇單丁醚進(jìn)行全面的審查，并對(duì)相應(yīng)濃度對(duì)健康和環(huán)境的影響進(jìn)行全面的審查之后，環(huán)境保護(hù)局得出結(jié)論，乙二醇單丁醚的潛在露天暴露不會(huì)給人類的健康少環(huán)境帶來(lái)可能的危害。” 

環(huán)境保護(hù)局在它的法規(guī)提案里面，在受影響的最大值和最低毒性作用水平之間，為安全性（“危害商數(shù)”）規(guī)定了范圍很廣的機(jī)動(dòng)處理權(quán)力。環(huán)保局發(fā)現(xiàn)人體接觸的次數(shù)應(yīng)當(dāng)比預(yù)計(jì)的沒(méi)有健康風(fēng)險(xiǎn)的次數(shù)低16到50次。因此，環(huán)境保護(hù)局做出結(jié)論：“本局認(rèn)為[乙二醇單丁醚] 對(duì)人類健康和環(huán)境影響的潛在作用非常的弱，因此有理由認(rèn)為這類不良影響不會(huì)產(chǎn)生。”參見(jiàn)（2003年11月21日）聯(lián)邦公告68-65648號(hào)文件。

乙二醇醚研究小組于1997年8月完成了乙二醇單丁醚的情況報(bào)告。環(huán)境保護(hù)局于2003年11月21日提交了它的規(guī)定提案，隨后收到了15條贊同意見(jiàn)。反對(duì)意見(jiàn)只有三條，內(nèi)容也不多，都是批評(píng)環(huán)境保護(hù)局沒(méi)有提供實(shí)質(zhì)性的資料，反對(duì)除名的意見(jiàn)。 

將乙二醇單丁醚從名單上刪除，糾正了有害空氣污染物名單過(guò)長(zhǎng)的弊病，這個(gè)名單是十多年前由國(guó)會(huì)制定的。早在二十世紀(jì)八十年代初期， 在動(dòng)物身上進(jìn)行的最簡(jiǎn)單的乙二醇醚化合物（乙二醇甲醚、乙二醇乙醚及其醋酸鹽）的研究，產(chǎn)生了一些有關(guān)這些化學(xué)品可能的毒性再生和擴(kuò)展的可能性的報(bào)告。后續(xù)的動(dòng)物研究顯示，乙二醇單丁醚并不會(huì)產(chǎn)生這種毒性。盡管這樣，那些關(guān)于乙二醇甲醚和乙二醇乙醚的報(bào)告還是讓所有類別的乙二醇醚上了國(guó)會(huì)的黑名單，名列1990年《清潔空氣法》修正案中提到的189種有害空氣污染物之中。

正如上面所提到的，環(huán)境保護(hù)局重新審查了國(guó)家毒理學(xué)規(guī)劃處1990年對(duì)嚙齒動(dòng)物的壽命研究。環(huán)保局除名情況說(shuō)明書中說(shuō)，環(huán)保局的科學(xué)家和同級(jí)的研究小組做出結(jié)論：“沒(méi)有現(xiàn)象表明，雖然乙二醇單丁醚及其同類化合物會(huì)在老鼠身上產(chǎn)生腫瘤，但不會(huì)導(dǎo)致人體發(fā)生癌變。既然沒(méi)有癌變，也就不會(huì)產(chǎn)生腫瘤。”因此，環(huán)保局宣布：“環(huán)境保護(hù)局得出結(jié)論，人類不會(huì)由于乙二醇單丁醚在環(huán)境中的集中而引發(fā)腫瘤。”

其他專家對(duì)乙二醇單丁醚的審查

其它政府和獨(dú)立專家小組也對(duì)乙二醇單丁醚數(shù)據(jù)進(jìn)行了審查。 

美國(guó)環(huán)境保護(hù)局對(duì)國(guó)家毒理學(xué)規(guī)劃處的腫瘤研究結(jié)果，即類似機(jī)制不會(huì)對(duì)人體產(chǎn)生類似影響的結(jié)論，得到歐盟（EU）化學(xué)制品標(biāo)簽專家委員會(huì)的贊同，該委員會(huì)確定乙二醇單丁醚不會(huì)產(chǎn)生標(biāo)簽上提示的致癌可能。歐盟正在對(duì)乙二醇單丁醚及其醋酸鹽進(jìn)行風(fēng)險(xiǎn)評(píng)估，評(píng)估工作有望于2005年完成。

美國(guó)化妝品成分審查委員會(huì)（CIR）專家建議小組在2002年對(duì)他們1996年的研究報(bào)告做了審查，得出的結(jié)果為“如果頭發(fā)和指甲用品中的乙二醇單丁醚濃度不超過(guò)10.0%，都是安全的。” 與歐盟和環(huán)境保護(hù)局一樣，美國(guó)化妝品成分審查委員會(huì)審查了國(guó)家毒理學(xué)規(guī)劃處的研究，同樣認(rèn)為對(duì)人體無(wú)害。

目前已知，只有加拿大衛(wèi)生部在國(guó)家毒理學(xué)規(guī)劃處的乙二醇單丁醚嚙齒動(dòng)物腫瘤研究中發(fā)現(xiàn)，乙二醇單丁醚可能會(huì)對(duì)人類帶來(lái)危害。2003年，加拿大提出針對(duì)老鼠出腫瘤的質(zhì)疑。加拿大的評(píng)估發(fā)表在網(wǎng)站：www.ec.gc.ca/cceb1/eng/public/glyclos_e.html 上。

環(huán)境中的乙二醇單丁醚

對(duì)乙二醇單丁醚排放到土壤、水和空氣中以后表現(xiàn)出來(lái)的特性，以及它對(duì)環(huán)境的影響已經(jīng)進(jìn)行過(guò)研究（主要成份C.A.，以及其它：乙二醇醚：環(huán)境風(fēng)險(xiǎn)評(píng)估。臭氧層36（7）, 1585-1613 （1998））。

乙二醇單丁醚由于其高溶解性、低揮發(fā)性和不易與土壤或沉積物結(jié)合的特性，因而大多聚集在水中，而在水里的時(shí)候，它的降解速度很快——其半衰期不到兩個(gè)星期。通過(guò)各種實(shí)驗(yàn)方案進(jìn)行的研究表明，乙二醇單丁醚不論是在有氧的水面、或者是在典型的廢物處理廠條件下，都符合美國(guó)環(huán)境保護(hù)局關(guān)于“易于”生物降解的規(guī)定。在空氣中，已經(jīng)發(fā)現(xiàn)乙二醇單丁醚的半衰期不到兩天。

只有在濃度很高的情況下乙二醇單丁醚才會(huì)對(duì)魚(yú)類和其它生物產(chǎn)生毒性，這種情況由于對(duì)乙二醇單丁醚的濃度要求非常高，所以已被列入美國(guó)環(huán)境署的“特殊無(wú)毒”類別。通過(guò)對(duì)海藻、酵母菌、原生動(dòng)物、細(xì)菌以及霉菌蛋白酶的測(cè)試，同樣證明乙二醇單丁醚不會(huì)給環(huán)境帶來(lái)不良影響，除非環(huán)境中的乙二醇單丁醚濃度大大高于歷史記錄。加拿大政府在2003年也發(fā)現(xiàn)乙二醇單丁醚不會(huì)對(duì)環(huán)境帶來(lái)危害。Tracy

只有在濃度很高的情況下，才發(fā)現(xiàn)乙二醇單丁醚會(huì)對(duì)魚(yú)類和其它生物產(chǎn)生毒性，在這種情況下乙二醇單丁醚的濃度之高，已經(jīng)可以被列入美國(guó)環(huán)境保護(hù)局“完全無(wú)毒（practically non-toxic）”的類別。通過(guò)對(duì)海藻、酵母菌、原生動(dòng)物、細(xì)菌以及霉菌蛋白酶的測(cè)試，同樣證明乙二醇單丁醚不會(huì)給環(huán)境帶來(lái)不良影響，除非環(huán)境中的乙二醇單丁醚濃度大大高于歷史記錄。加拿大政府在2003年也發(fā)現(xiàn)乙二醇單丁醚不會(huì)對(duì)環(huán)境帶來(lái)危害。

環(huán)境保護(hù)局的審查以及將乙二醇單丁醚從《清潔空氣法》有害空氣污染物名單上取消，同樣也是因?yàn)橐叶�醇單丁醚的排放不可能給予環(huán)境還來(lái)不良影響。

職業(yè)接觸極限（2004年制定的乙二醇單丁醚值）

世界各地的指導(dǎo)和規(guī)章制定機(jī)構(gòu)已經(jīng)對(duì)乙二醇單丁醚制定出了職業(yè)接觸極限值，并規(guī)定了皮膚接觸警告值。某些機(jī)構(gòu)的數(shù)據(jù)如下表所示。可以咨詢下表中列出的機(jī)構(gòu)，以獲得有關(guān)這些極限值的更詳細(xì)信息。

美國(guó)政府工業(yè)衛(wèi)生工作者會(huì)議（ACGIH TLV，美國(guó)）
 20 ppm
 97 mg/m3
 
允許接觸極限（美國(guó)職業(yè)安全與衛(wèi)生管理局 – PEL，美國(guó)）
 50 ppm
 242 mg/m3
 
極限值說(shuō)明（ILV - 歐盟）
 20 ppm
 97 mg/m3
 
工作場(chǎng)所最大允許濃度（MAK- 德國(guó)）
 20 ppm
 97 mg/m3
 
職業(yè)接觸標(biāo)準(zhǔn)（OES – 英國(guó)）
 20 ppm
 121 mg/m3
 
在各種各樣的工作場(chǎng)地中測(cè)量到的乙二醇單丁醚空氣濃度，都大大低于上述極限值。

關(guān)于乙二醇單丁醚毒性的更詳細(xì)的信息，請(qǐng)參考以下文獻(xiàn)：

R·J·波特曼和J·B·肯納克，餡餅毒理學(xué)，第86章，約翰·威利父子公司2001年出版；R·J·波特曼、R·A·克雷、T·格林、J·E·克勞寧和M·M·烏登，對(duì)B6C3F1老鼠乙二醇單丁醚誘發(fā)腫瘤病理的審查，以及該病理對(duì)人類健康風(fēng)險(xiǎn)評(píng)估的價(jià)值，J·托克斯，《衛(wèi)生》（英文版B部分，7：385-398（2004）。

本文總結(jié)了技術(shù)和科技文獻(xiàn)的資料，對(duì)醫(yī)學(xué)、科研和規(guī)章制定的人員起到參考作用。美國(guó)化學(xué)品委員會(huì)的乙烯基和丙烯基乙二醇醚研究小組及其會(huì)員公司認(rèn)為，這個(gè)文件，包括文件公布的數(shù)據(jù)，都是根據(jù)現(xiàn)有科學(xué)資料所得出的最準(zhǔn)確的數(shù)據(jù)。 但是該小組及其會(huì)員公司不會(huì)對(duì)所公布數(shù)據(jù)的完整性和準(zhǔn)確性做任何承諾、說(shuō)明或者暗示，也不會(huì)為這些數(shù)據(jù)的使用承擔(dān)責(zé)任和義務(wù)。這個(gè)摘要的后續(xù)實(shí)驗(yàn)會(huì)產(chǎn)生新的數(shù)據(jù)，并對(duì)摘要中不完全和不正確的地方進(jìn)行修正。該小組及其會(huì)員公司在摘要出版以后，沒(méi)有對(duì)摘要中的數(shù)據(jù)進(jìn)行修改、校正、取消或者更新的義務(wù)和責(zé)任。

2005年6月

本資料由美國(guó)化學(xué)品委員會(huì)乙烯基和丙烯基乙二醇醚小組及其會(huì)員公司發(fā)表：奧麒化工、道化學(xué)公司、伊斯特曼化學(xué)公司、�？�斯特化學(xué)公司、LP和利安德化學(xué)公司。

乙二醇醚是一組應(yīng)用非常廣泛的化學(xué)制品，其主要用途包括：涂料溶劑、清潔劑和墨水等。某些乙二醇醚只用于工業(yè)用途；其它乙二醇醚廣泛地應(yīng)用于工業(yè)、商業(yè)用途和消費(fèi)品。

所有投入商業(yè)市場(chǎng)的乙二醇醚都在動(dòng)物身上進(jìn)行過(guò)潛在毒性的研究。這些乙二醇醚研究的摘要由很多政府部門、學(xué)術(shù)單位和工業(yè)研究人員管理，其內(nèi)容可以在《餡餅業(yè)的衛(wèi)生和毒理》（2001年第五版第七卷第86章）和歐洲生態(tài)毒理學(xué)和毒理學(xué)中心（ECETOC）技術(shù)報(bào)告（2005年第64號(hào)乙二醇醚的毒性及其對(duì)人體的影響）。這些數(shù)據(jù)已經(jīng)用于產(chǎn)品的使用說(shuō)明。

乙二醇醚已經(jīng)受到媒體的關(guān)注，并被列入某些政府的有害物質(zhì)名單，原因是發(fā)現(xiàn)摩爾量最小的乙二醇醚可能會(huì)對(duì)男性和女性生殖產(chǎn)生不良影響，并通過(guò)對(duì)嚙齒動(dòng)物的研究發(fā)現(xiàn)它對(duì)動(dòng)物的出生會(huì)產(chǎn)生不良影響。這些乙二醇醚在美國(guó)過(guò)去二十年中一直用于消費(fèi)品。其它的乙二醇醚也經(jīng)過(guò)同樣的測(cè)試，但是發(fā)現(xiàn)不會(huì)產(chǎn)生類似的影響，因此用于更廣泛的用途。

乙二醇醚資料的更新

乙二醇單丁醚（EGBE）
 的環(huán)境特點(diǎn)

瑞有的科學(xué)數(shù)據(jù)顯示，乙二醇單丁醚（EGBE）這種用途廣泛的化學(xué)產(chǎn)品，不會(huì)在環(huán)境中長(zhǎng)期存在，不會(huì)在生物體內(nèi)積累，對(duì)水生生物完全無(wú)毒，因此對(duì)環(huán)境的不良影響極輕或者根本沒(méi)有。除了上述特點(diǎn)外，乙二醇單丁醚的其它品質(zhì)還包括：在按照規(guī)定操作的情況下，對(duì)人體的不良影響可以降到最低，同時(shí)它也具備獨(dú)特的特點(diǎn)，可以同時(shí)用于極性化合物和非極性化合物的溶劑。

物理性質(zhì)

乙二醇單丁醚由于揮發(fā)性低（蒸汽壓力介于0.6和0.88毫米汞柱之間），易于溶解于水，并且不易與土壤結(jié)合（辛醇/水分配系數(shù)（log Kow）值為0.81至0.83）。在溶于水中時(shí)，乙二醇單丁醚在水生生物體內(nèi)的積累量可以忽略不計(jì)（計(jì)算出的生物積累量值為2.5）.

降解

乙二醇單丁醚在環(huán)境中不會(huì)持續(xù)存在。在空氣中，它的半衰期不到兩天，在水中的半衰期少于兩個(gè)星期。通過(guò)各種實(shí)驗(yàn)方法把乙二醇單丁醚劃分為“易于”或者“天生”可生物降解的類別，這種分類同時(shí)適用于有氧的水面、或者是在典型的廢物處理廠條件。

水生生物毒性

環(huán)境保護(hù)局將乙二醇單丁醚水生生物測(cè)試結(jié)果歸類為“完全無(wú)毒”。分別在七條魚(yú)身上進(jìn)行的急性毒性測(cè)試表明，致命濃度（半數(shù)致死劑量）應(yīng)當(dāng)至少達(dá)到800毫克/升（mg/L）；對(duì)無(wú)脊椎動(dòng)物的測(cè)試，致命濃度（半數(shù)致死劑量）應(yīng)當(dāng)高于500 mg/L。在對(duì)藻類、酵母菌、原生動(dòng)物和霉菌蛋白酶的測(cè)試，同樣說(shuō)明除非在極高的濃度下，乙二醇單丁醚不會(huì)對(duì)環(huán)境造成不良影響。

綜述

由于本身的物理性質(zhì)，因?yàn)槟軌蚩焖俳到獠粫?huì)長(zhǎng)時(shí)間保存在水中，所以大多數(shù)乙二醇單丁醚都排放到環(huán)境中。結(jié)果是，乙二醇單丁醚表現(xiàn)出不穩(wěn)定性，而且很難在環(huán)境中積累到很高的濃度。對(duì)魚(yú)類和水生生物的不良影響因此可以忽略。不過(guò)，有關(guān)環(huán)境中的乙二醇單丁醚的各種報(bào)告都是在大大低于危害濃度的情況下做出的。總而言之，乙二醇單丁醚是一種不穩(wěn)定的、無(wú)生物積累的、“完全無(wú)毒”的溶劑，而且有令人滿意的環(huán)保特性。

本文總結(jié)了技術(shù)和科技文獻(xiàn)的資料，對(duì)醫(yī)學(xué)、科研和規(guī)章制定的人員起到參考作用。美國(guó)化學(xué)品委員會(huì)的乙烯基和丙烯基乙二醇醚研究小組及其會(huì)員公司認(rèn)為，這個(gè)文件，包括文件公布的數(shù)據(jù)，都是根據(jù)現(xiàn)有科學(xué)資料所得出的最準(zhǔn)確的數(shù)據(jù)。 但是該小組及其會(huì)員公司不會(huì)對(duì)所公布數(shù)據(jù)的完整性和準(zhǔn)確性做任何承諾、說(shuō)明或者暗示，也不會(huì)為這些數(shù)據(jù)的使用承擔(dān)責(zé)任和義務(wù)。這個(gè)摘要的后續(xù)實(shí)驗(yàn)會(huì)產(chǎn)生新的數(shù)據(jù)，并對(duì)摘要中不完全和不正確的地方進(jìn)行修正。該小組及其會(huì)員公司在摘要出版以后，沒(méi)有對(duì)摘要中的數(shù)據(jù)進(jìn)行修改、校正、取消或者更新的義務(wù)和責(zé)任。