In the
United States Court of Appeals
For the Seventh Circuit

No. 00-2950

Willard S. Peterson,

Plaintiff-Appellant,

v.

Wal-Mart Stores, Inc.,

Defendant-Appellee.




Appeal from the United States District Court
for the Central District of Illinois.
No. 98-1384--Joe Billy McDade, Chief Judge.


Argued December 12, 2000--Decided February 22, 2001



 Before Bauer, Posner, and Kanne, Circuit Judges.

 Posner, Circuit Judge. The plaintiff fell on the
tile floor of the aisle of a Wal-Mart where he
was shopping, and severely injured his knee. A
broken can of women’s shaving lotion was found
nearby; the plaintiff had slipped on lotion
spilled from the can. Two employees of Wal-Mart
testified by deposition that they had walked down
the aisle just minutes before the accident and
had seen no sign of spillage, but the plaintiff
testified that he had been waiting in the aisle
for his wife for ten minutes and during that time
had neither seen any employees nor heard any
sound of breakage. Concluding that the lotion had
been on the floor for four or at most ten
minutes, the district court, citing Hresil v.
Sears, Roebuck & Co., 403 N.E.2d 678 (Ill. App.
1980), granted summary judgment for Wal-Mart,
holding that under Illinois’ common law of
negligence (which the parties agree governs Wal-
Mart’s liability in this diversity case) ten
minutes are too few to give a storeowner
constructive notice of a hidden danger in his
premises. The plaintiff’s testimony, if believed
(and a jury could have believed it), established
that the spill had occurred at least ten minutes
before the accident, but there is no basis in the
record for estimating how much earlier the spill
might have occurred, and so, since the plaintiff
had the burden of proof, the district court was
correct to treat ten minutes as the outside
limit.

 A business owes its customers, as invitees, the
duty to take reasonable care to avoid injuring
them. E.g., Wiegman v. Hitch-Inn Post of
Libertyville, Inc., 721 N.E.2d 614, 624 (Ill.
App. 1999); Miller v. National Ass’n of Realtors,
648 N.E.2d 98, 100 (Ill. App. 1994); Vernon v.
Kroger Co., 712 N.E.2d 976, 979 (Ind. 1999);
Restatement (Second) of Torts sec.sec. 332(1),
(3), and comment e; 343(c) (1965). The floors of
large self-service general stores like Wal-Mart
are smooth, the customer traffic heavy, and the
danger of spillage that is caused by customers or
employees who accidentally knock bottles or other
containers off a shelf and that can precipitate a
fall that may cause serious injury, especially to
elderly customers, who are numerous, is
significant. The store’s duty is not merely to
prevent careless spillage by its employees but
also to be on the lookout for spillage by
whomever caused and to clean it up promptly.
E.g., Tomczak v. Planetsphere, Inc., 735 N.E.2d
662, 667 (Ill. App. 2000); Howard v. Wal-Mart
Stores, Inc., 160 F.3d 358, 359 (7th Cir. 1998)
(Illinois law); Love v. Hardee’s Food Systems,
Inc., 16 S.W.2d 739, 742-43 (Mo. App. 2000);
Golba v. Kohl’s Dept. Store, Inc., 585 N.E.2d 14,
15 (Ind. App. 1992). Satisfaction of the latter
half of this duty, the duty of inspection and
clean up, does not require continuous patrolling
of the aisles, Hresil v. Sears, Roebuck & Co.,
supra, 403 N.E.2d at 680; Howard v. Wal-Mart
Stores, Inc., supra, 160 F.3d at 359; Taylor v.
J.M. McDonald Co., 56 N.W.2d 610, 613 (Neb.
1953); the cost would be disproportionate to the
benefit. But it may require, in self-service
stores where customer traffic is heavy and the
probability of a slip and fall therefore high
(both because there are many people using the
aisles, who are customers rather than employees,
and because the probability that a customer
through spillage or otherwise will create a
hazardous condition is a function of the number
of customers per square foot of floor), frequent
and careful patrolling. See, e.g., Love v.
Hardee’s Food Systems, Inc., supra, 16 S.W.2d at
744; Golba v. Kohl’s Dept. Store, Inc., supra,
585 N.E.2d at 17; Robinson v. F.W. Woolworth &
Co., 420 So. 2d 737, 740-41 (La. App. 1982). The
cost of such patrolling to the store need not be
high. Employees have frequent occasion to be in
the store’s aisles in any event; they have only
to be alert to the possibility of spillage to
notice it and clean it up promptly.

 There is no evidence that any of Wal-Mart’s
employees were aware of the spillage that caused
the plaintiff’s injury and failed to clean it up;
and there is, as we have pointed out, no duty of
continuous inspection. But neither is there any
flat rule in Illinois that ten minutes is always
too short a period for a duty of inspection and
clean up to arise; at least Hresil does not
announce such a rule, for the court there pointed
to facts, such as that the store was not busy
(and so the likelihood of spillage less), that
made ten minutes too short a time in the
circumstances of that case to indicate a lack of
care. Cf. Jackson v. Delchamps, Inc., 691 So. 2d
332, 335 (La. App. 1997); Johnson v. Tayco Foods,
475 So. 2d 65, 68 (La. App. 1985).

 Wal-Mart hurt itself (as it did in Howard v.
Wal-Mart Stores, Inc., supra, as we noted in our
opinion there) in two ways. The first was by
presenting evidence (just as it had done in Gump
v. Wal-Mart Stores, Inc., 5 P.3d 407, 409 (Haw.
2000)) that its employees patrol the aisles
constantly for signs of spills. This implies, if
the plaintiff’s testimony is believed (and a jury
could believe it without taking leaves of its
senses), that the employees may have been
careless not to have noticed the spilled lotion.
Second, while it is certainly arguable that ten
minutes is too short a time to establish a
storeowner’s negligence in failing to have
noticed and corrected a dangerous condition
caused by a customer, see, e.g., Walker v. Golub
Corp., 714 N.Y.S.2d 796, 797 (App. Div. 2000);
Dwoskin v. Burger King Corp., 671 N.Y.S.2d 494
(App. Div. 1998) (per curiam); Maiorano v. Price
Chopper Operating Co., 633 N.Y.S.2d 413 (App.
Div. 1995); Jackson v. Delchamps, Inc., supra,
691 So. 2d at 335; A.B.C. Drug Co. v. Sweat, 432
S.E.2d 627 (Ga. App. 1993); Smith v. Winn-Dixie
Atlanta, Inc., 417 S.E.2d 202 (Ga. App. 1992);
Reed v. Kroger Co., 400 So. 2d 1106 (La. App.
1981); but see Schon v. National Tea Co., 274
N.E.2d 578, 581-82 (Ohio App. 1971), Wal-Mart
limits its argument on this score to the
groundless claim that the Hresil case established
such a rule. It did not. And maybe every aisle in
a typical Wal-Mart store is traversed by an
employee at least once every ten minutes, in
which event a ten-minute safe harbor might not be
the right rule for this case. That is a matter to
be explored at trial, if the case doesn’t settle
first. The grant of summary judgment was error.

Reversed and Remanded.
