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+-------------------------+---------------------------+--------------+---+
| Ronald L. Shubkin,      |                           |              |   |
| Manager - Technical     |                           |              |   |
| Services, **Tel**:      |                           |              |   |
| (225) 751-7778**,       |                           |              |   |
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Air Radiation Docket

Environmental Protection Agency

Attn: Docket ID No. OAR 2002 0064

Re: Comment on Flammability of n-Propyl Bromide as Discussed in Proposed
Rule Published in Federal Register Vol. 68, No. 106, June 3, 2003.

The discussion of flammability (Section IV-D) in the Proposed Rule is
generally accurate, but becomes confused by the undocumented reference
(on page 33303) to reports of flashpoints for n-propyl bromide (nPB).
These reports are wrong and misleading. Also, no reference is made to
the reports of flashpoint tests carried out by independent laboratories
and submitted to the EPA. These reports show conclusively that n-propyl
bromide does not have a flashpoint. n-Propyl bromide has been repeatedly
tested following the ASTM D56 (Tag Closed Cup) and the ASTM D93
(Pensky-Martens Closed Cup) protocols, and it has never exhibited a
flashpoint. It has also failed to show a flashpoint under various "open
cup" methods such as the Cleveland Open Cup.

Some of the confusion in reporting the results of flashpoint testing
lies in the definition of a flashpoint. A flashpoint test consists of
passing a pilot light over the surface of the liquid being tested. If
the vapors of a liquid are flammable (i.e., capable of sustaining
combustion), the flame front will propagate from the pilot light to the
liquid surface. The temperature at which this flame propagation happens
is called the flashpoint. The National Fire Protection Agency (NFPA)
gives a number of definitions of flashpoint in its Glossary of Terms,
but they all include the phrase, "The minimum temperature at which a
liquid gives off vapor sufficient to form an ignitable mixture in air
**near the surface of the liquid**." n-Propyl bromide does not exhibit
this behavior under the conditions of the ASTM D56, the ASTM D93 or the
Cleveland Open Cup methods.

The vapors of n-propyl bromide can be combusted in an external source of
ignition. The result of this characteristic in the performance of a
flashpoint test is that the pilot light may be briefly enhanced before
it is extinguished. In this case, the enhanced flame is **above the
pilot light and not near the surface of the liquid**, as required by the
various NFPA definitions. Enhancement of the pilot light is also typical
of hydrochlorocarbons that are classified as non-flammable (i.e.,
methylene chloride, trichloroethylene, etc.). The mistaken
interpretation of pilot light enhancement for flashpoint has led at
times to the erroneous identification of n-propyl bromide as a flammable
liquid. This was particularly true in the earlier literature, and the
misrepresentation could be found in many standard databases, including
literature from some of the manufacturers of n-propyl bromide.

Another source of misinformation concerning the flammability of n-propyl
bromide has come from the determination of flashpoints outside of the
acceptable temperature range for the test being employed. Dr. Elisabeth
Brandes of the German National Flammables Laboratory presented data to
the European Chemicas Bureau (ECB) that indicated that n-propyl bromide
has a flashpoint of -10°C. The ECB was reviewing the flammability status
of n-propyl bromide for the European Commission (EC). The International
Brominated Solvents Association (IBSA) commissioned Chilworth Technology
Limited in the U.K. to determine if the data from Dr. Brandes were
valid. In a report from Chilworth Technology, Dr. Stephen Rowe
(Technical Manager, Process Safety Laboratory) reported that n-propyl
bromide does have a flashpoint of --5°C to --1°C when measured using the
Pensky-Martens non-equilibrium apparatus employed by Dr. Brandes. He
also found that dichloromethane (methylene chloride) has a flashpoint
using this method. However, Dr. Rowe points out that the method employed
is not valid outside the temperature range of +10°C to +110°C. He states
that the temperature range is clearly stated in the ISO 1523 standard.
He goes on to add that there are alternative methods detailed in ISO
1523 which are valid down to --30°C. These methods include the Abel, Tag
and Abel-Pensky apparatus. In fact, Dr. Brandes had reported no
flashpoint for n-propyl bromide when using these alternative, valid
methods.

Dr. Rowe also tested three non-flammable fluorocarbon ether solvents
using the Pensky-Martens closed cup method employed by Dr. Brandes. In a
report to IBSA dated May 10, 2002, Dr. Rowe states that he found
ignition for HFE-72DE at --9°C, for HFE-71DE at --16°C, and for HFE-71DA
at --14°C. The "non-flammable" status of these solvents has never been
questioned.

Finally, under the Occupational Safety and Health Standards (29 CFR
1910.1200) of OSHA, a flammable liquid is defined as having a flashpoint
at or above 100°F (37.8°C), but below 200°F (93.3°C). n-Propyl bromide
has no flashpoint up to its boiling point of 71°C, and clearly is
non-flammable under this definition.

Sincerely Yours,

Ronald L. Shubkin, Ph.D., MBA

Manager, Technical Services

Richard DeGroot

Director, Research and Development

Dov Shellef

President

Poly Systems USA, Inc.