Shiva Purana
परमास्त्रं च शैवानां भस्मैतत्पारमेश्वरम् ॥ धौम्याग्रजस्य तपसि व्यापदो यन्निवारिताः ॥ ९७ ॥
This Bhasma is a great weapon of the devotees of Śiva. It is a divine missile whereby the mishaps of the elder brother of Dhaumya in the course of his penance had been removed.
english translation
paramAstraM ca zaivAnAM bhasmaitatpAramezvaram ॥ dhaumyAgrajasya tapasi vyApado yannivAritAH ॥ 97 ॥
hk transliteration by Sanscript