Last year on Lag Bo’omer some of my neighbors made a customary bonfire. When they finished, they poured lots of water on the fire, extinguishing the flames completely. However, the next day the coals burst into flames once again, and before the fire department could extinguish the flames many of the flowers in my backyard were destroyed, causing me a loss of three hundred dollars. Are my neighbors liable for the damage? If they are, is there any particular individual who is responsible?
If all the fires were extinguished and all they left behind was hot coals, probably they are not liable.
There is a Mishna (Bava Kama 59B) which discusses your situation. The Mishna says, “If the wind blew and created a fire they (those who brought the raw materials, including the source of fire) are not liable.” The Yerushalmi (cited by Tosafos s.v. Leebso and many others) explains that the wind which the Mishna is referring to is not an unusual wind like a hurricane but even a wind that “sometimes blows and at other times does not blow.”
There is a dispute among the Rishonim how to understand the Yerushalmi.
Tosafos and the Rashbo understand that the wind which is referred to (“sometimes blows and at other times does not blow”), is categorized as a ruach she’eina metsuya – an unusual wind. Just like one is liable if a usual wind (a ruach metsuya) spread his fire to another place, so too he is liable if a usual wind created the fire. It is only when an unusual wind created the fire that the ones who brought the raw materials are not liable. However, since the Yerushalmi described this wind as being one which sometimes blows, these Rishonim understand that even a wind which is not an infrequent occurrence is classified as an unusual wind. Therefore, according to them, those who brought the raw materials are liable only if either the wind that eventually created the fire was already blowing at the time when they brought the raw materials, or if the flames were caused by a constant wind. Anything else is classified as an unusual wind for which one is not liable.
Therefore, according to the approach of the Rashba, if the wind which was blowing at the time they left the coals was not sufficient to ignite a fire and the wind that did ignite the fire was not the constant breeze that blows regularly, they would not be liable.
There is a second approach to understanding the Yerushalmi. The Tosafos Rabbeinu Peretz (and Re’o brought by the Shitto Mekubetses) disagrees with Tosafos and the Rashba, and explains that the wind referred to by the Yerushalmi (“sometimes blows and at other times does not blow”) is classified as a ruach metsuya. However, there is a difference between one’s liability for an existent fire and one’s liability for the creation of a fire. Whereas, one is responsible for a fire if an ordinary wind can spread it from one place to another, the Mishnah teaches us that one is not liable even if a usual wind can ignite the fire. One is only liable for the wind’s igniting a fire if the wind which was blowing at the time that he left the raw materials was at least as strong as the wind which eventually ignited the fire.
Whereas, there are many halachic differences between the two approaches (and the Chazon Ish (Bava Kama 2, 6), who discusses one such case, rules that it is a sofeik which opinion is authoritative), in your situation there won’t be a difference. Even according to the approach of Rabbeinu Peretz they would not be liable unless the wind that eventually ignited the fire was blowing at the time when they left the extinguished fire.
Various Acharonim (e.g. Kuntressei Hashiurim siman 17, Imrei Moshe siman 29) explain that the reason that those who, in a sense, caused the fire are not liable is because the Torah limited liability for a fire to one who can be described as a “mav’ir es hab’eiyroh,” one who set the fire. One who acted as your neighbors did cannot be considered a “mav’ir es hab’eiyroh,” since there is too much that he did not do.
You asked further if there is any individual who would be liable in case they are liable. Based on the above discussion, the case where someone is liable is where there is testimony or proof that the wind that eventually ignited the fire was blowing at the time they departed from the scene, or else if they did not completely extinguish the fire. In order to determine who is responsible in those cases, we must recall a ruling of the Rambam and Shulchan Aruch (418, 7). They rule that if one is appointed to watch over a fire, that person assumes liability for any resultant damages.
Therefore, it would depend. If there was an individual or a few individuals who accepted responsibility to extinguish the flames, he/they would be liable for the damages. However, if no one accepted responsibility, liability will remain with the one who originally started the fire. The Mishna, cited earlier, further states that if two people jointly create a fire, where one person brings the wood and the other brings the fire, whoever acted last is responsible. Since the way people make a Lag Bo’omer bonfire is that they first form a woodpile and then set the pile ablaze, the one who was honored to light the bonfire would be liable unless he left early and those remaining assumed responsibility for extinguishing the bonfire.