Zevachim12: 5
פָּרִים הַנִּשְׂרָפִים וּשְׂעִירִים הַנִּשְׂרָפִים — בִּזְמַן שֶׁהֵם נִשְׂרָפִין כְּמִצְוָתָן, נִשְׂרָפִין בְּבֵית הַדֶּשֶׁן, וּמְטַמְּאִין בְּגָדִים; וְאִם אֵינָן נִשְׂרָפִין כְּמִצְוָתָן, נִשְׂרָפִין בְּבֵית הַבִּירָה, וְאֵינָם מְטַמְּאִין בְּגָדִים.
The bulls that are burned and the hegoats that are burned — when they are burned according to their proper procedure, they are burned in the place of ashes, and they contaminate garments with tumah; but when they are not burned according to their proper procedure, they are burned in the palace precinct, and they do not contaminate garments with tumah.
Zevachim12: 6
הָיוּ סוֹבְלִין אוֹתָם בְּמוֹטוֹת. יָצְאוּ הָרִאשׁוֹנִים חוּץ לְחוֹמַת הָעֲזָרָה, וְהָאַחֲרוֹנִים לֹא יָצְאוּ, הָרִאשׁוֹנִים מְטַמְּאִין בְּגָדִים, וְהָאַחֲרוֹנִים אֵינָן מְטַמְּאִין בְּגָדִים עַד שֶׁיֵּצְאוּ. יָצְאוּ אֵלּוּ וָאֵלּוּ, אֵלּוּ וָאֵלּוּ מְטַמְּאִין בְּגָדִים. רַבִּי שִׁמְעוֹן אוֹמֵר: אֵלּוּ וָאֵלּוּ אֵינָן מְטַמְּאִין בְּגָדִים עַד שֶׁיִּצֶּת הָאוּר בְּרֻבָּן; נִתַּךְ הַבָּשָׂר, אֵין הַשּׂוֹרֵף מְטַמֵּא בְגָדִים.
They would carry them on poles. When those in front have emerged beyond the wall of the Courtyard, and those in the rear have not [yet] emerged, those in the front contaminate [their] garments with tumah, while those in the rear do not contaminate [their] garments with tumah until they emerge. When [both] these and those have emerged, both these and those contaminate [their] garments with tumah. Rabbi Shimon says: Neither these nor those contaminate [their] garments with tumah until the fire catches on to most of them; [and] once the meat has become charred, the one who burns [them] does not contaminate [his] garments with tumah.