Dow Corning Corporation — Hazardous Materials Safety Interpretation

Page 1U.S. Deportment of Transportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Avenue. SE Washington, OC 20590 MAR 1 20lD Mr. Stephen V. Moser Assistant General Counsel Dow Corning Corporation Midland, Michigan 48686-0994 Ref. No.: 09-0273 Dear Mr. Moser: This responds to your letter dated November 9,2009 regarding the proper hazard classification for Chlorosilanes products under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). Specifically, you ask whether Chlorosilanes products currently not classed as Division 4.3 (Dangerous When Wet) materials in the § 172.101 Hazardous Materials Table (§ 172.101 HMT) meet the definition in § 173. 124(c) for a Division 4.3 (Dangerous When Wet) material. According to your letter, you are seeking reaffirmation of your understanding of a previous letter, dated March 18, 1998, from the International Standards Coordinator for Hazardous Materials Safety to Ms. Laura Neuwirth, Lathan & Watkins, that discusses subsidiary labeling requirements for materials that meet Division 4.3 criteria. You did not provide sufficient information (e.g., hazard characteristics, material safety data sheet (MSDS» for this Office to make a determination concerning the classification of your Chlorosilanes products. Under § 173.22 ofthe HMR, it is the shipper's responsibility to properly classify a hazardous material. This Office does not perform that function. As you are aware, the § 172.10 I HMT specifically lists the basic description "Trimethylchlorosilane, 3, UN 1298, II", as a Class 3 (Flammable liquid) material with a subsidiary hazard of Class 8 ( Corrosive). The proper labels for a Class 3 material having a subsidiary hazard of Class 8 are the FLAMMABLE LIQUID and CORROSIVE hazard warning labels. However, it is the shipper's responsibility to determine ifa material has any other subsidiary hazards that require subsidiary hazard labels or placards under the provisions of §§ 172.402 and 172.505, respectively. Such determinations are not required to be verified by this Office. If your material meets the definition for a Division 4.3 material as specified in § 173. 124(c), then the shipping paper must note the Division 4.3 subsidiary hazard and the#

Page 2package must bear a Division 4.3 label, whether or not the Division 4.3 subsidiary hazard is indicated in the §172.101 HMT entry for the material. I hope this information is helpful. If we can be of further assistance, please contact us. Sincerely, laL~~ . ef, Standards Development Office ofHazardous Materials Standards#

Page 3eDOW GORNING [Y/j rulV1 c§ 11 Z. lor g 113. fZY ~) November 9, 2009 ~ II Z. Ll 02 (cc.x..Z) ~ (12 . SO~) ? l QC.u.rd I ':jU.S. Department of Transportation PHMSA Office of Hazardous Materials Standards 09- 0213 Attn: PHH-10 East Building 1200 New Jersey Avenue, S.E. Washington, DC 20590-0001 Re: Request for Clarification Dear SirlMadam: Dow Coming Corporation (DCC) has determined that a number of its chlorosilanes meet the definition of Dangerous When Wet (DWW) as set forth in 49 CFR Section 173 .124( c), but are not already classified as D WW in the Hazardous Materials Table (49 CFR 172.101, the "Table"). For the reasons explained below, DCC respectfully requests that PHMSA confirm that it is proper for DCC to label and placard these chlorosilanes as a subsidiary DWW hazard, based on the requirements of49 CFR 172.402(a)(2) (relating to subsidiary hazard labels) and 49 CFR 172.505(c) (relating to placarding for subsidiary hazards). To put this request in full context and assist PHMSA in its consideration ofthe issue presented, we offer the following additional information. Attached are two letters from 1998 between Frits Wybenga, U.S. DOT, and Latham & Watkins, then legal counsel to the Silicones Environmental Health and Safety Council (SEHSC), addressing in part this subject. Also attached is a letter DCC has provided to carriers and officials since 1998 explaining why certain chlorosilanes are labeled and placarded as they are. Recently, however, a tanker carrying trimethylchlorosilane was stopped by a New York State trooper. The trooper and other state transportation officials with whom he conferred (NYSDOT) concluded that the shipment was improper because a DWW placard was affixed to the tanker and the shipping papers referenced a subsidiary DWW hazard when there is no specific reference to Division 4.3 in Column 6 of the Table for trimethylchlorosilane. According to NYSDOT, DCC must use only shipping references and placards consistent with the specific hazard codes identified in the Table for the listed material and may not reference or placard for any other subsidiary risk without special approval from U.S. DOT. When provided with copies of the 1998 letters noted above, NYSDOT stated that these letters were ambiguous and not satisfactory to establish the requisite U.S. DOT approval. NYSDOT recommended that we seek clarification from PHMSA; hence, this request. Attached Dow Corning Corporation Midland, Michigan 48686·0994 Phone: (989) 496·4000 www.dowcorning.com#

Page 4U.S. Department of Transportation November 9, 2009 Page 2 for your easy reference is a copy of the recent letter we sent to NYSDOT concerning this matter. Dow Coming is committed to safely transporting its products on America's highways and takes seriously its obligations to comply with the letter and spirit of all applicable transportation safety regulations. We firmly believe it is our legal obligation (and the proper interpretation of the regulations and the Wybenga letter) to placard as DWW any and all products that meet the Division 4.3 criteria, whether that hazard is specifically identified in the Table or not. Thus, we disagree with NYSDOT's interpretation of the regulations as applied to our ongoing shipments of trimethylchlorosilane and similarly situated chlorosilanes. However, we do agree that PHMSA is the best authority in this instance to address the propriety of our practices. Thank you for your attention to this matter. If you have questions or require further information, please let me know. I can most easily be reached by telephone at (989) 496-5843 or email atsteve.moser@dowcorning.com. We look forward to hearing from you at your earliest opportunity. Very truly yours, ~tl.~ Stephen V. Moser Assistant General Counsel Dow Coming Corporation Attachments#

Page 5LATHAM & WATKINS IODI DCANSILVANTA AVE NI ATTORMETS AT LAW MET ALMORT OFFICE ETIC ATO Stat liage gure s4ñd MASIONGION, DC 20004•2305 Sult a00 rESCENDer, 12014 2101811 TAN 13051 00J 0101 TELEPHOME 1202: 037•2200 HERBOR UNISEC Dai sutie ranies that broca SAX 18021831 270% HİS YOHN HEW SORR 1002* a99) aRE THIRD AVENUE QUITE IODID TELEPHONE 1212I 00G1100 ra6 1 44-171-2a 4400 4448-514 aaaa LOS CHEELED CALORNIA CONTI POOR asa mess fifTH aracEt, durie daon costa miza, CALiTOGNA 02020-1025 TELEPHONE I TINI 5401258 TELEGMUNE 1 P13= 105 183. TAR +78d 755-8200 12812131 gur-aTax SAR ALRE ARIS BALAN CREICE January 27, 1998 POL "B' BISECT. SUItE 2-00 TElEPHonE • 7.303 009.5455 4x•7007ag9.sa8e scow, Ruse area TELEPHOnE 1000) 130-1830 120 10191 004:7419 PAI I HIE, 308.0001 BY MESSENGER Frits Wybenga International Standards Coordinator Robert A. Richard Assistant International Standards Coordinator RSPA, DHM5, Room 8422 U.S. Department of Transportation 400 7th Street, S.W Washington, D.C. 20590-0001 Charles H. Ke Chief, Sciences Group Office of Hazardous Materials Technology, Room 8430 U.S. Department of Transportation 400 7th Street, S.W. Washington, D.C. 20590-0001 Re: SEHSC Proposal On The Regulation Of Materials That Emit Toxic Gas When Wet Dear Messrs. Wybenga, Richard and Ke: On behalf of the Silicones Environmental Health and Safety Council ('SEHSC"), 1 want to express our appreciation for the time and attention you have given to SEHSC's proposal concerning the regulation of hazardous materials that emit toxic gas when wet, which we submitted to the U.S. Department of Transportation ("DOT") on March 21, 1997. In particular, we appreciate the opportunity we had to meet with you on March 26, 1997, to discuss the recommendations in our proposal. This letter serves to confirm DOT's comments on SEHSC's proposal that were made during our March#

Page 6LATHAM & WATKINS Frits Wybenga Robert A Richard Charles H Ke January 27, 1998 Page 2 26th meeting and to convey the commitment of SEHSC's members to implement handling and labeling practices no later than the end of 1998 in accordance with this proposal on a voluntary basis. A. Use of the "Dangerous When Wet" Label SEHSC's proposal recommends that the "dangerous when wet" ("DWW") label be used as a subsidiary risk label for all chlorosilanes not currently classified as DWW by DOT, until such time as the Agency is able to revise its regulatory framework in a manner that both requires and allows shippers of chlorosilanes to classify and label their materials. During our meeting, we reviewed the deficiencies in DOT's regulations that prevent shippers of chlorosilanes and other similar water reactive materials from determining whether the evolution of toxic gas from such materials when in contact with water is a primary or secondary hazard. You indicated that SEHSC could use the DWW label as a subsidiary risk label for chlorosilanes not already classified as DWW if these chemical substances otherwise meet the definition of DWW as set forth in 49 C.F.R. § 173.124(c). As you are aware, the current DWW label has a flame on it which does not indicate the toxic hazard of some DWW materials. For chlorosilanes that are DWW because they emit toxic gas when wet, DOT suggested that shippers also use either a poisonous by inhalation label or a marking explaining the nature of the DWW hazard. In particular, Fritz Wybenga suggested that, in addition to a DWW subsidiary risk label, shippers of chlorosilanes may want to place text on their containers that states "emits toxic gas when wet." SEHSC members have decided to adopt Mr. Wybenga's suggestion for the labeling of domestic shipments of chlorosilanes, except for shipments of "limited quantities" - meaning quantities not exceeding 2 liters. B. Clarification of the DWW Test Procedure In addition to the labeling issue, SEHSC explained to DOT, both in its written proposal and at the March 26th meeting, that the DWW test procedure fails to specify how much water to use in determining whether a material is in fact DWW. See Appendix E to 49 C.F.R. § 173.124(c). Based on our limited testing results, we noted that the amount of water used in testing a particular chlorosilane for evolution of flammable or toxic gas may determine whether that substance should be classified as DWW. At our meeting, you indicated that it would be appropriate to conduct such testing on a "worst case" basis. In other words, if a material emits toxic or flammable gas in sufficient quantities to satisfy the DWW threshold when tested with any amount of water, then it should be classified as DWW.#

Page 7LATHAM &Watkins Frits Wybenga Robert A Richard Charles H. Ke January 27, 1998 Page 3 You also verbally approved the use of theoretical calculations, in addition to actual testing, to determine whether water reactive materials are in fact DWW. The flexibility to use theoretical calculations avoids the need for repetitive testing of materials with various amounts of water to determine the "worst case" release of flammable or toxic gas. This flexibility is especially helpful with chlorosilanes, the reactivity of which may vary significantly depending on the quantity of water involved in testing such substances. C. Harmonization Between DOT Regulations and U.N .. Recommendations We understand that, at this time, DOT does not plan to act on SEHSC's long term proposal to (i) create a new Division 4.4 and label with a skull and crossbones for materials that emit toxic gas when wet, and (ii) revise the Precedence of Hazard Table to rank the DWW-toxic'''' hazard in relation to other hazards listed in the Table. You have informed us that DOT prefers to wait until the ongoing harmonization efforts with the United Nations ("U.N.") Recommendations on the Transport of Dangerous Goods are concluded. You also indicated, however, that the Agency would be supportive of a broader, industry-wide proposal to the U.N .. on how to regulate materials that emit toxic gas when wet. SEHSC is most interested in working with its counterpart in Europe - the Centre Europeen Des Silicones ("CES") - to present an industry-wide proposal to the U.N .. on DWW-toxic materials. Shortly after our meeting with DOT, we requested that the CES review and comment on SEHSC's long-term proposal. We also have set up a conference call meeting between the CES and SEHSC Operating Safety Committees to discuss all relevant DWW issues and to explore the possibility of an industry-wide position on the classification and labeling of chlorosilanes. We will keep you apprised of significant developments on this matter. * * * Once more, we express our appreCiation for your consideration of SEHSC's proposal. We would appreciate it if you could confirm in writing the accuracy of our understanding of DOT's position on the issues noted above -- in particular, (i) the use of the DWW label as a subsidiary risk label for all chlorosilanes not already classified as DWW (assuming they meet the DWW threshold); (ii) the use of theoretical calculations rather than actual testing to determine whether the DWW threshold is exceeded for a particular water reactive material; and (iii) implementation of the DWW testing procedure on a "worst case" basis.#

Page 8LATHAM & WATKINS Frits Wybenga Robert A. Richard Charles H. Ke January 27, 1998 Page 4 My colleague, Greg Slater, has relocated from the Washington, D.C. area. Thus, if you have any questions concerning this letter or SEHSC's proposal to DOT, please do not hesitate to contact me at (202) 637-2239, or SEHSC's Executive Director, William Smock, or Deputy Director, Beth Dombrowsky, at (703) 438-3943. Very truly yours, Julia A. Hatcher of LATHAM &WATKINS cc: William H. Smock SEHSC, Executive Director Elizabeth C. Dombrowsky, SEHSC Deputy Director SEHSC DWW Work Group Members DC DOCS\56247.1#

Page 9Dow Coming INTERNAL " US Department of Transportation Washington, D.C. 20590 400 Seventh Street S. W, Research and Special Programs Administration Laura Neuwirth Latham & Watkins Attorneys at Law 1001 Pennsylvania Avenue, NW Washington, DC 20004-2505 Dear Ms. Neuwirth: This is in response to your letter of January 27, 1998 recording your understanding of the meeting held between representatives of Silicones Environmental Health & and Safety Council and representatives from our office on March 26, 1997 We concur with your summary of points discusses at the meeting. However, in relation to subsidiary risk labeling it should benoted that 172.402(a)(2) requires the use of the 4.3 subsidiary risk label for substances meeting the Division 4.3 criteria. Sincerely, Frits Wybenga International Standards Coordinator for Hazardous Materials Safety Title:dotletter DWW Page 1 of 2#

Page 10Dow Coming INTERNAL Title:dotletter DIJIMI Page 2 of2#

Page 11Dow Coming INTERNAL May 26,1998 To: Interested Parties From: Dow Corning Corporation Transportation Regulatory Team Subject: Addition of Dangerous When Wet (DWW) Subsidiary Hazard to C h lorosilanes The purpose of this letter and the attached letter from the DOT is to explain why many chlorosilanes being shipped domestically by road and rail by Dow Corning Corporation have been re-classified as a subsidiary Dangerous When Wet. Hopefully, this correspondence will address any confusion you may have regarding the domestic transportation of these materials. Dow Corning Corporation recently reclassified many chlorosilanes that were not already classed as DWW by the DOT, as a subsidiary DWW. This reclassification is ONLY for domestic transportation. This reclassification was based on recent limited testing and knowledge of the nature of chlorosilanes that indicated that these materials meet the definition of Dangerous When Wet in 49 CFR 173.124(c). Dow Corning Corporation and the Silicones Environmental Health and Safety Council (SEHSC) met with the DOT regarding this issue. In summary, it was determined that the Dow Corning Corporation and other the SEHSC member companies will start labeling and/or placarding chlorosilanes as a subsidiary DWW hazard, if not already classed as a DWW by the DOT to meet the requirements of 172.402(a)(2) and 172.505(c). In addition, it was agreed upon by the DOT that Dow Corning would also add an additional statement near the label and/or placard that reads "Emits Toxic Gas When Wet". This explains why many chlorosilanes now are transported domestically as a subsidiary DWW and carry a statement that reads "Emits Toxic Gas When Wet". Wayne Winslow Sr. Transportation Safety and Regulatory Specialist /Attachment: DOT Letter Dated March 18, 1998 letterDCC dw Page 1 of 1#

Page 12October 9,2009 Justin Zimmerman Motor Carrier Investigator New York State Dept ofTransportation 11 Valley park Drive, Adams, NY 13605 Dear Mr. Zimmerman: Thank you for taking the time this morning to talk wIth me and other representatives ofDow Coming's Transportation Compliance team. I thought it was a helpful discussion, even ifwe could not come to a full agreement on the application ofthe Hazardous Materials Transportation Regulations (49 CFR Parts 100-185, the "HMR") to certain shipments ofDow Coming products. The purposes ofthis letter are: (I) to confirm Dow Coming's conunitment to follow up with the U.S. Department ofTransportation, Pipeline and Hazardous Materials Safety Administration ("U.S. DOT" or "PHMSA"); and (2) to document the gist ofour discussion this morning. We want to avoid any confusion or misunderstanding regarding Dow Coming's knowledge of, and commitment to full compliance with, the HMR. We also want to assure the safe and timely movement ofour products in transit. As we discussed, you recently stopped a tanker carrying trimethylchlorosilanethat had a Dangerous When Wet ("DWW") placard on it. Dow Coming interprets the HMR to require such a placard. We base this on our knowledge of the hazards ofthe chemicals we produce and transport and our reading ofthe requirements relating to identification ofsubsidiary hazards, found in 49 CFR Sections 172.101(g), 172.402(a) and 172.505(c). We also base our interpretation on the March 19, 1998 letter from Frits Wybenga ofU.S. DOT, written in response to a submission from the Silicones Environmental Health and Safety Council on this subject (the "Wybenga letter"). From our discussion we have a better understanding ofyout concerns regarding the use ofa DWW placard when a material, like trimethylchlorosilane, is listed in the Hazardous Materi.als Table (49 CFR 172.101, the "Table") but there is no specific reference to Class 43 in Column 6 ofthe Table for that material. In short, we understand that your interpretation ofthe HMR is that Dow Coming must use only placards consistent with the specific hazard codes ideptified in the Table for the listed material and may not placard for any other subsidiary risk without special approval from U.S. DOT. You explained that you did not find the Wybenga letter satisfactory to establish such U.S. DOT approvaL Dow Corning Corporation Midlantl. Michig;m 4l!6R6-/}<}94 Phone: (989)496-4000#