Q: On Lag BaOmer, I made a bonfire that spread and burned a pile of lumber in an adjacent yard. The owner claims that some valuable tools had been hidden in the lumber. Am I liable for them?

A: From the verses regarding fire damage, the Sages derive that one is not liable for something that is tamun — concealed or covered. This leniency applies only if one lit the fire on his own property, but not if he lit the fire on another’s property without permission. It is questionable whether it applies to a fire lit in a public domain (C.M. 418:13; Pischei Choshen, Nezikin 9:[12,56]).

Even if one lit the fire on his own property, if it spread continuously, he is liable according to most authorities. Only if there was a protective, intervening wall that fell — not on account of the fire — is he exempt (see P.C., Nezikin 9:21).

Intended fire, arson, is considered adam hamazik and the leniency of tamun is not relevant (Shach 418:6).

Thus, unless you lit the bonfire on your property and there was an intervening wall, you are liable for the tools, even though they were covered. The owner is believed, with an oath, that they were there, if it is reasonable.