הַנְּבֵלָה אָב מֵאֲבוֹת הַטֻּמְאוֹת. כְּזַיִת מִבְּשָׂרָהּ מְטַמֵּא אָדָם וְכֵלִים בְּמַגָּע וּכְלֵי חֶרֶס בַּאֲוִיר. וּמְטַמֵּא אֶת הָאָדָם בְּמַשָּׂא לְטַמֵּא בְּגָדִים כְּמֶרְכַּב הַזָּב. כֵּיצַד. אָדָם שֶׁנָּגַע בִּנְבֵלָה נִטְמָא וַהֲרֵי הוּא רִאשׁוֹן לְטֻמְאָה. וְאִם נָגַע בְּכֵלִים אֲפִלּוּ בִּשְׁעַת מַגָּעוֹ בִּנְבֵלָה הֲרֵי הֵן טְהוֹרִין. וְכֵן כֵּלִים שֶׁעָלָיו טְהוֹרִין לְפִי [שֶׁהוּא] וָלָד וְאֵין וָלָד מְטַמֵּא כֵּלִים. אֲבָל הַנּוֹשֵׂא אֶת הַנְּבֵלָה מְטַמֵּא כֵּלִים בִּשְׁעַת נְשִׂיאָתוֹ שֶׁנֶּאֱמַר (ויקרא יא כח) "וְהַנּשֵֹׁא אֶת נִבְלָתָם יְכַבֵּס בְּגָדָיו". וְאוֹתָן הַבְּגָדִים רִאשׁוֹן לְטֻמְאָה. וְאֵינוֹ מְטַמֵּא לֹא אָדָם וְלֹא כְּלֵי חֶרֶס וַאֲפִלּוּ בִּשְׁעַת נְשִׂיאָתוֹ כְּמוֹ שֶׁבֵּאַרְנוּ בִּמְטַמְּאֵי מִשְׁכָּב וּמוֹשָׁב:
The carcass of a dead animal is a primary source of impurity. An olive-sized portion of its meat imparts impurity to a person and keilim when touched and to an earthenware container when it enters its inner space. And it imparts impurity to a person when being carried to the extent that his clothes become impure, as is the law regarding a surface on which one rides that contracted impurity from a zav. What is implied? When a person touches the carcass of a dead animal, he is considered as a primary derivative of impurity. If he touches keilim - even at the same time that he is touching the carcass - they are pure. Similarly, the clothes that he is wearing are pure, for he is a derivative of impurity and a derivative does not impart impurity to keilim. When, by contrast, one carries the carcass of a dead animal, he imparts impurity to keilim while he is carrying it, as Leviticus 11:28 states: "One who carries their carcasses must launder his garments." Those garments are considered as primary derivatives of impurity. He does not impart impurity to another person or to earthenware containers even when he is carrying the carcass, as we explained in Hilchot Metamei Mishkav UMoshav.
