All the experts involved in various Bernzomatic litigations are reputable. Here are three for now -
Thomas Eager Click here to see Mr. Eager's depo. transcript
MIT, 77 Massachusetts Ave, Cambridge, MA 02139-4307, tel. 617-253-1000
2. Dr. Robert Anderson Click
to see Dr. Anderson Report 1, Report 2, Report 3
Saddle Court, Los Altos Hills, CA 94022-1810, tel. 650-949-1092
3. Thomas Crane, P.E.
Polaris Lane North, Plymouth, MN 55447-4777, tel. 763-557-0710
In some ways Dr. Thomas Eager, Worthington's expert witness in some of the litigations, provides the strongest supporting evidence
of a product defect. Quoting from a deposition taken September 10, 2008, Dr. Eager testifies as to the amount of force one must
exert to the tip of the torch to cause the MAPP cylinder to breach -
"[the amount of force required to breach the cylinder] is not something that you do with your wrist. It is not something that you
do with your wrist and your elbow. This is something that you have to do with your shoulder on. Okay. Let me just say that...I have
to use my shoulder into it. I have to have leverage of the length from my shoulder to my hand."
As Dr. Eager testified, he apparently was not aware of the existence of the fracture groove. The amount of force he specified
would break the fracture groove, not rupture the cylinder. The fracture grooves do not break...indeed a problem, as described
Dr. Anderson performed a stress test on the cylinder and torch handle. The conclusions establish with "engineering certainty"
the existence of a defect in that many cylinders breach at well below 15 foot-pounds of force, while the torch handles fracture at
the safety fracture groove at about 22-26 foot-pounds (26 ft. lbs. being the likely common figure) -
The fracture grooves tested broke at 22-23 foot pounds on the torch tip design shown on the right. The torch tip was re-designed
June 2005. The new design is even worse in that it fractured at 26 foot-pounds of force.
The cylinder was stress-tested below the the fracture groove as well. The test results reveal that absent a defect, the cylinder
will bend, as shown in the photo above, at 15 foot-pounds of force. This means that any cylinder breaching without first bending
as shown in the photo will have necessarily breached at below 15 foot-pounds of force.
A great number of the cylinders are defective, as shown in this photograph of a cylinder purchased new in September 2008 (above).
The joint is clearly not joined properly to the top of the cylinder. Compare to the weld of the bent cylinder (a "good" one),
Dr. Anderson's testing reveals that the weld at the neck joint (below the threads) often is full of voids, and often is
corroded. It appears that the MAPP gas itself causes corrosion at this area in some instances, while generally the manufacturing
process itself produces several cylinders with insufficient welding material. It appears that most of the cylinders which have breached
and caused injuries were manufactured by Worthington, since most litigations were filed after the manufacturing transition to Worthington
In all known instances of breaches of the cylinders, the breaches were always at the same joint, and in no instance did the cylinders
bend first, nor did the torch handle fracture grooves ever break as intended. Here are photos of some of the actual cylinders.
All the litigations were filed between the years 2004 and 2008. We know of no litigation involving propane gas. All breached
cylinders known to date contained MAPP gas. As of April 30, 2008 "MAPP" was no longer produced, and Worthington replaced it
with "MAP" gas under the Worthington label. It appears the cylinders continue to be designed with deficient joints, though whether
or not the added problem of corrosion will exist with the new gas is not known at this time. Worthington disclosed it sold about
21 million units over a two or three year period, apparently between the years 2005 and 2008. Many of the "MAPP" cylinders remain
on the market as of the date of this publication.
Re: MAPP gas Explosions and Injuries