Aceto Corporation — Hazardous Materials Safety Interpretation

Page 1U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Ave, S.E. Washington, D.C. 20590 JUL 2 3 2013 Ms. Suhey Francisco Sr. Regulatory Affairs Specialist Aceto Corporation 4 Tri Harbor Court Port Washington, NY 11050 Ref. No.: 13-0073 Dear Ms. Francisco: This is in response to your March 12, 2013 email requesting clarification on acute toxicity test requirements for inhalation toxicity in the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). According to the information in yo~r letter, you have classified your material Methylene- his( 4-cyclohexylisocyanate) or synonym Cyclohexane, 1,1 '-methylenebis[ 4-isocyanato- (CAS# 5124-30-1) using publicly available test data as UN2206, Isocyanates, toxic, n.o.s., 6.1, PG II. The acute toxicity test data values used in your classification are as follows: LC5o Rat (male, head only exposure to an aerosol) inhalation 0.295 mg/L/4hr LC5o Rat (female, head only exposure to an aerosol) inhalation 0.307 mg/L/4hr After adjusting the four-hour exposure data in accordance with§ 173.132(b )(3)(i) you indicate the one-hour exposure results as LC50 Rat (male) 1.18 mg/L/1hr and LC50 Rat (female) 1.228 mg/L/lhr. In accordance with the§ 173.133(a)(l) table, this material is assigned to packing group II. Specifically, you seek clarification on the suitability of test result data as the exposure was to an aero so 1 and not to either a dust or mist as prescribed in § § 1 73 .13 2 and 1 73 .13 3 and if these results should be applied when classifying your material. The answer to your question is yes. The test results would be applicable when exposure is administered as a liquid aerosol that emerges as a mist, if a mist is likely to be generated in a leakage of the transport containment as prescribed in§ 173.132(b)(3)(iii). As provided in § 173.22, it is the shipper's responsibility to make this determination. In addition, you also request clarification that if the aforementioned test method 1s not appropriate for determining the toxicity of the material, would it still require classification as UN2206, Isocyanates, toxic, n.o.s., Class 6.1, because of its chemical family.#

Page 2Under§ 173.22 of the HMR it is a shipper's responsibility to properly classify a hazardous material. A poisonous material (liquid) is defined in§ 173.132 as a material, other than a gas, which is presumed to be toxic to humans because it falls within one of the following categories when tested on laboratory animals: oral toxicity, dermal toxicity and inhalation toxicity. If your material meets the LC:;o or LD50 criteria for any of these categories, it meets the definition of a Division 6.1 material. Thus, if your material meets the definition of a Division 6.1, or any other hazard class, then it must be classified accordingly, an.i the determination should not be based solely on its chemical family. I hope this information is helpful. If you have further questions, please do not hesitate to contact this office. V1/ Delmer Billings Senior Regulatory Advisor Standards and Rulemaking Division#

Page 3Aceto Corporation 4 Tri Harbor Court Port Washington, NY 11050 Tel: (516) 627 6000 Fax: (516) 627 6093 www.aceto.com U.S. Department of Transportation Office of Hazardous Materials Standards Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Avenue, SE Washington, DC 20590-0001 March 8, 2013 Re: Interpretation of test data values for LC50 inhalation rat in accordance to 49 CFR § 173 .132(b)(3). Dear Sir or Madam: Aceto Corporation is requesting from the Associate Administrator for Hazardous Materials Safety a clarification on the test result requirements for LC50 toxicity data values for inhalation rat Using publically available test data, we have classified our material Cyclohexane, 11 '- Methylenebis(4-isocyanato- [CAS# 5124-30-1 J as UN2206, Isocyanates, toxic, n.o.s., Class 6.1, PG ll. However, it has come to our attention that because of the method of testing, this material may not be subject to the classification. The test data values we have are the following: LC50 Rat (male, head only exposure to an aerosol) inhalation 0.295 mg/LI4hr LC50 Rat (female, head only exposure to an aerosol) inhalation 0.307 mg/L/4hr Once the test data has been adjusted in accordance with 49 CFR § 173 .132(b )(3)(i), the test data are LC50 Inhalation Rat l. 18 mg/L/1 hr and LC50 1.228 mg/L/1 hr respectively. This would place the material as packaging group I L However, due to the exposure as an aerosol and not a dust/mist as specified in the regulations, some sources have argued that this would exempt the material from its hazardous classification. Does the test method of exposure as an aerosol affect the toxic classification of the material? further to that, Aceto has classified the material as an isocyanate, which is specifically listed in the hazardous materials table. If the test method is not appropriate for determining toxicity of the material,#

Page 4wouldn't it still require classification as UN2206, Isocyanates, toxic, n.o.s. because of its chemical family? Aceto appreciates your attentiveness to this matter and looks forward to your Jesponse. If you have any questions or concerns, please feel free to contact me by phone at 5 I 6-627-6000, ext 596 OJ by email at sfranciscoUiJaceto.com. Sincerely, \ Suhey Francisco Sr. Regulatory Affairs Specialist Aceto Corporation#