What is the obligation regarding a deceased person found in a well containing toxic fumes?

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If a person dies in a well containing fumes, extraction must occur if possible by treating the well with wet coverings to draw out the vapors, followed by descending to retrieve the body, or by using hooks without mutilation (mathla). This is obligatory because washing the deceased is possible without causing harm, analogous to handling a body on open ground. If there is doubt about the fumes' dissipation, a lamp or similar light source is lowered; if it extinguishes, the vapor remains, but if it stays lit, the vapor has dissipated, as fire only remains where living things can survive.