In most cases, tort law is based on fault. In some narrow circumstances, there can be liability without fault (aka strict liability). However, in general in order for there to be liability without fault the damage must be direct. For example, in the case of Sullivan v. Dunham (161 N.Y. 290, 55 N.E. 923 (1900)), Dunham was blowing up tree stumps with explosives. One of the stumps flew through the air and beaned Harten on the head as she walked on a public road, killing her. Although Dunham wasn't acting negligently, the Court found that this act rose to the level of trespass to person and Dunham was liable. The case turned on the fact that this was a direct harm. If the injury had been indirect (like if the stump landed in the road and Sullivan tripped over it later), then there could be no recovery. To make things even more complicated, sometimes the courts will find liability even if the damage is indirect, as long as it is "almost" direct. For example, in the case of Exner v. Sherman Power Construction Co. (54 F.2d 510, 80 A.L.R. 686 (2d Cir 1931)), Sherman was blowing up explosives. Exner was lying in her bed next door when the concussion wave hit and knocked her out of bed. The Court found that there would be recovery under the concept of trespass, even though this was more of an indirect harm than a direct harm like was found in Sullivan. The Court basically said that there is really no difference.