Narrated Ibn `Abbas (RAA):

concerning the verse, “And if you are ill or on a journey...” (an-Nisa': 43). He said, "If a man sustains a wound, which he suffered during Jihad (in the cause of Allah) or ulcers, then he became junub (sexually impure) and is afraid that if he bathes he would die; he may perform ablution with clean earth (Tayammum). [Reported by Ad- Daraqutni in a Mawquf (untraceable) Hadith and Al-Bazzar in a Marfu' (traceable) one. Ibn Khuzaima and Al-Hakim graded it Sahih (sound)].

وَعَنِ ابْنِ عَبَّاسٍ رَضِيَ اَللَّهُ عَنْهُمَا فِي قَوْلِهِ عَزَّ وَجَلَّ ﴿ وَإِنْ كُنْتُمْ مَرْضَى أَوْ عَلَى سَفَرٍ ﴾ [1]‏ قَالَ:

إِذَا كَانَتْ بِالرَّجُلِ اَلْجِرَاحَةُ فِي سَبِيلِ اَللَّهِ وَالْقُرُوحُ, فَيُجْنِبُ, فَيَخَافُ أَنْ يَمُوتَ إِنْ اِغْتَسَلَ: تَيَمَّمَ

.‏ رَوَاهُ اَلدَّارَقُطْنِيُّ مَوْقُوفًا, وَرَفَعَهُ اَلْبَزَّارُ, وَصَحَّحَهُ اِبْنُ خُزَيْمَةَ, وَالْحَاكِم ُ [2]‏ .‏