UNITED

NATIONS	ST

Secretariat	Distr.

GENERAL

ST/SG/AC.10/1998/1

22 July 1998

Original: ENGLISH
COMMITTEE OF EXPERTS ON THE

TRANSPORT OF DANGEROUS GOODS

(Twentieth session,

Geneva, 7-16 December l998,

agenda item 2 (d))

WORK OF THE SUB-COMMITTEE OF EXPERTS ON

THE TRANSPORT OF DANGEROUS GOODS

Draft amendments to the Model Regulations

on the Transport of Dangerous Goods

New proposals */

Additional Proper Shipping Name for Methyl Methacrylate	Monomer, Inhibited

Transmitted by the expert from the United States of America

Introduction

1.	For UN 1247, Methyl Methacrylate Monomer, Inhibited, the word "inhibited" is commonly interpreted to mean that the substance has been stabilized to avoid uncontrolled polymerization by the addition of a chemical inhibitor. Methyl Methacrylate Monomer can also be effectively stabilized by other means such as by temperature control. These methods are sometimes preferred because the inhibitor may not be desirable for use in certain industrial processes.

2.	In the case of shipments made without an inhibitor, the use of the word "INHIBITED" as a part of the proper shipping name is confusing. It is proposed that the proper shipping name be revised to correct this.

3.	During its seventeenth session, the Committee considered this same issue with respect to "VINYL CHLORIDE, INHIBITED". The Committee revised the entry to read "VINYL CHLORIDE, INHIBITED or VINYL CHLORIDE, STABILIZED". This facilitated the transport of the substance when shipped stabilized without a chemical inhibitor.

4.	In the United States, methyl methacrylate monomer has been successfully and safely shipped in bulk quantities under temperature control for many years, without creating any unsafe conditions due to polymerization.

Proposal

5.	It is proposed that the proper shipping name for METHYL METHACRYLATE MONOMER, INHIBITED be amended to read:

METHYL METHACRYLATE MONOMER, INHIBITED or

METHYL METHACRYLATE MONOMER, STABILIZED

6.	A consequential amendment should also be made to the index.

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