                          In the
 United States Court of Appeals
              For the Seventh Circuit
                       ____________

No. 04-1933
MARINETTE MARINE CORPORATION and
SIGNAL MUTUAL INDEMNITY ASSOCIATION,
                                                  Petitioners,
                              v.

OFFICE OF WORKERS’ COMPENSATION PROGRAMS,
MYRON BAUMLER, and CRUM & FORSTER MANAGERS
CORPORATION OF ILLINOIS,
                                      Respondents.
                    ____________
                Petition for Review of an Order
                 of the Benefits Review Board.
                        No. 03-BRB-0380
                       ____________
 ARGUED SEPTEMBER 7, 2005—DECIDED DECEMBER 12, 2005
                    ____________


 Before BAUER, POSNER, and EVANS, Circuit Judges.
  EVANS, Circuit Judge. After years of working in the
shipbuilding industry, Myron Baumler needed back sur-
gery. The question in this case is which of two workers’
compensation carriers should pay for it; the answer depends
on whether Baumler injured his back once or twice. An
administrative law judge (ALJ) found that a first injury in
1997 was aggravated by a second injury in 2001, so he
assigned liability to the carrier at the time of the second
injury, consistent with the “aggravation rule” of maritime
2                                              No. 04-1933

workers’ compensation law. The carrier insists that there
was no second injury in 2001 and that Baumler’s worsened
condition was just the natural progression of his 1997
injury. We need to decide whether the ALJ’s contrary
finding is worthy of deference.
  During most of his 30 years with Marinette Marine
Corporation, Baumler has been a sheet metal press worker.
The sheets of metal he works with are heavy, sometimes
weighing up to 300 pounds. On April 8, 1997, as Baumler
was carrying one of these sheets with a coworker, the
coworker’s grip failed and the sheet fell, hitting Baumler’s
foot just above his reinforced boot. Although no serious
injury was immediately apparent, Baumler eventually
began to feel pain in his lower back and right leg. An
electromyography (EMG) and a magnetic resonance imag-
ing test (MRI) suggested that a disc in Baumler’s lower
back had become displaced. This led to a first round of back
surgery in early 1998, paid for by Marinette Marine’s
workers’ compensation carrier at the time, Crum & Forster
Insurance.
  Baumler stayed away from heavy work for the next
year and a half while his surgeon, Dr. Max Ots, kept an eye
on his condition. Additional EMG and MRI tests showed
some degeneration but no unusual changes, and by mid-
1999 Baumler was cleared to return to the plate shop with
restrictions on the amount he could lift. He was still in
some pain, but given the difficulty of further treatment,
Dr. Ots thought it best to leave well enough alone, barring
a worsening of symptoms.
  In July 2001, Baumler returned to Dr. Ots to report a
recent increase in pain, which he ascribed to an incident at
work 2 months earlier. On May 22, 2001, as he was step-
ping onto a 5-inch ledge to measure the curvature of a piece
of metal, Baumler’s back locked up. For 3 to 5 minutes he
was unable to straighten his leg, and it took another 15
No. 04-1933                                                3

minutes of walking around before the cramping sensation
subsided. He was then able to resume working, but over the
next couple of months the pain in his leg and back became
progressively worse. Dr. Ots ordered more tests, which
convinced him that the displacement of Baumler’s lower-
back disc had become more severe and that surgery was
now in order.
  But there was a problem: Marinette Marine had switched
workers’ compensation insurance carriers, and the new
carrier, Signal Mutual Indemnity Association, refused to
authorize surgery. According to Signal, Baumler’s lower-
back trouble was unrelated to the May 2001 incident
(Signal calls it a mere “cramping” incident) but instead was
the natural development of his earlier condition. And
because Signal was not the carrier for Marinette Marine
when that earlier condition arose, it did not consider itself
liable for Baumler’s surgery and disability.
  It fell to an ALJ at the U.S. Department of Labor to
decide what role, if any, the May 2001 incident played in
worsening Baumler’s symptoms. Each side—Baumler joined
by Crum & Forster against Signal and Marinette Marine—
presented testimony from board-certified orthopedic
experts. Dr. Kenneth Yuska, testifying on Baumler’s behalf,
stated that his condition was caused by a combination of the
incidents of April 1997 and May 2001, the more recent one
bearing about 25 percent of the blame. The opposing side’s
expert, Dr. Richard Lemon, disagreed: Baumler’s back
troubles were simply the result of old age and had nothing
to do with either of the two work incidents. Baumler’s
treating physician, Dr. Ots, expressed a view somewhere in
between: although he was convinced that the April 1997
incident was the primary cause of Baumler’s condition, he
also allowed that the May 2001 incident might have helped
make that condition worse.
 The ALJ evaluated the evidence under the Longshore and
Harbor Workers’ Compensation Act, 33 U.S.C. § 901 et seq.
4                                                No. 04-1933

Two parts of his analysis are relevant to this appeal. First,
the ALJ considered whether Baumler’s claim was compen-
sable—that is, whether the injury arose in the course of
Baumler’s employment. See 33 U.S.C. § 902(2); U.S. Indus./
Fed. Sheet Metal, Inc. v. Director, OWCP, 455 U.S. 608, 615
(1982). Under § 920(a) of the Act, once certain preliminary
showings have been made, it is presumed, “in the absence
of substantial evidence to the contrary,” that the claim
“comes within the [Act’s] provisions.” See American Grain
Trimmers, Inc. v. OWCP, 181 F.3d 810, 813-14 (7th Cir.
1999) (en banc). In this case, the ALJ found, Baumler made
his preliminary prima facie case by showing that (1) he
suffered a harm, and (2) conditions existed at his workplace
that could have caused the harm. The ALJ asked whether
Signal and Marinette could rebut the resulting presumption
of compensability. He acknowledged Dr. Lemon’s testimony
that Baumler’s back troubles were unrelated to work, but
he considered the contrary view of Drs. Yuska and Ots to be
“better reasoned and documented.” He therefore found the
presumption unrebutted, and so he concluded that
Baumler’s injury arose in the course of his employment.
  The ALJ then had to determine which insurer was liable
for the injury. If Baumler’s condition was the natural
progression of his April 1997 injury, then responsibility
would fall to Crum & Forster, the insurer at the time of
that injury. But if the May 2001 incident aggravated the
earlier injury, then Signal would be responsible for the
entire cost—a principle known as the “aggravation rule.”
See New Haven Terminal Corp. v. Lake, 337 F.3d 261, 267
(2nd Cir. 2003); Travelers Ins. Co. v. Cardillo, 225 F.2d 137,
144-45 (2nd Cir. 1955). Again, the ALJ was persuaded by
the opinion of Drs. Yuska and Ots that the May 2001
incident had an aggravating effect on Baumler’s earlier
injury, so he found Signal to be the responsible carrier.
 Signal and Marinette appealed the ALJ’s decision to the
Benefits Review Board, arguing primarily that the ALJ
No. 04-1933                                                  5

erred in his application of the § 920(a) presumption. They
insisted that they rebutted the presumption by produc-
ing evidence—Dr. Lemon’s testimony—that the injury
was not work-related, but the ALJ wrongly required
them to meet a burden of persuasion rather than produc-
tion. See American Grain Trimmers, Inc., 181 F.3d at 817
(the presumption of compensability is overcome by pro-
duction rather than persuasion). The Board agreed that this
was an error but concluded that it was harmless. After the
presumption is rebutted, the Board reasoned, the ALJ still
needs to determine on the record as a whole whether the
injury arose in the course of work. See id. at 819. And that,
in effect, is what the ALJ did—he weighed the testimony of
Dr. Lemon against the testimony of Drs. Yuska and Ots and
concluded that the latter outweighed the former. Finding
that conclusion to be rational and supported by substantial
evidence, the Board affirmed the ALJ’s decision.
   Signal and Marinette make several arguments challeng-
ing the Board’s and the ALJ’s conclusions. First, they argue
that Baumler did not even make out a prima facie case that
he had a claim under the Act. They insist that the locking
of Baumler’s back in May 2001 caused only temporary pain
and was therefore not an “injury” for which they can be
liable. But Baumler isn’t seeking compensation for his back
locking up—he’s seeking the cost of the surgery to get rid of
the chronic pain he suffered in the months that followed.
The petitioners can question whether the May 2001 incident
actually contributed to that pain, but they can’t realistically
say that Baumler didn’t suffer an injury.
  Signal and Marinette also argue that the ALJ’s deter-
mination of liability was tainted by his incorrect under-
standing of the § 920(a) presumption, so the error was not
harmless. They insist that it is unclear whether, in the
absence of that presumption, the ALJ would have found
that the May 2001 incident aggravated Baumler’s condition
and therefore that Signal was liable for the cost of surgery.
6                                                No. 04-1933

But this argument appears to confuse compensability with
liability. The § 920(a) presumption is about whether the
claimant’s injury is compensable—whether it happened in
the course of work—not about who has to pay for it. See
Buchanan v. Int’l Transp. Servs., 33 BRBS 32, 1999 WL
197777, at *4 (BRB 1999) (§ 920(a) “plays no role in the
determination of the responsible employer”). That question
is addressed by the aggravation rule, which is applied
without any presumptions, simply by “weighing . . . the
evidence of record.” Id. That’s what the ALJ did in this case,
after determining that Baumler’s claim was indeed compen-
sable. Signal and Marinette might have argued that the
claim was not compensable at all, based on Dr. Lemon’s
testimony that Baumler’s back troubles were simply the
result of old age. But instead they conceded at oral argu-
ment that Baumler’s condition was caused primarily by the
April 1997 workplace accident. So the § 920(a) presumption
is irrelevant, and the ALJ properly determined liability
without reference to it.
  The presumption aside, Signal and Marinette take
issue with the ALJ’s conclusion that the May 2001 inci-
dent was to blame for Baumler’s back condition several
months later. They point out that even Dr. Ots, Baumler’s
treating physician, testified that Baumler’s symptoms were
more or less a natural development from the April 1997
injury and only tentatively conceded that the May 2001
incident may have contributed to the worsening of those
symptoms. But Dr. Ots wasn’t the only physician on which
the ALJ relied—Dr. Yuska was unequivocal in his assess-
ment that the later incident was about 25 percent to blame
for Baumler’s condition. Also, the aggravation rule does not
require that a later injury fundamentally alter a prior
condition. It is enough that it produces or contributes to a
worsening of symptoms. See Bath Iron Works Corp. v.
Preston, 380 F.3d 597, 605 (1st Cir. 2004); Delaware River
Stevedores, Inc. v. Director, OWCP, 279 F.3d 233, 241
No. 04-1933                                             7

(3rd Cir. 2002); Kelaita v. Director, OWCP, 799 F.2d 1308,
1311-12 (9th Cir. 1986). Whether Baumler’s temporary back
spasm was able to do that is something we are not equipped
to decide—that was the ALJ’s call, and he made it based on
substantial evidence in the record.
  We therefore DENY the petition for review and AFFIRM the
decision of the Benefits Review Board.

A true Copy:
      Teste:

                       ________________________________
                       Clerk of the United States Court of
                         Appeals for the Seventh Circuit




                  USCA-02-C-0072—12-12-05
