There is nothing wrong in conducting business in the Dead Sea region as well as making the best use of that place in extracting certain materials for therapeutic purposes that are intended for conducting a halal business.
Dr. Muhammad Bakr Isma`il, professor of the Exegesis of the Qur’an at Al-Azhar University, states the following: Working and conducting business in such places -according to the way mentioned in the question – is not haram because such places have become urban, and densely populated. It is well known that most part of Arab lands were dwelt in by people of previous nations, and they were chastised by Allah Almighty due to their disobedience. For example, the people of `Aad, who were destroyed by the Wind, were inhabitants of Yemen. The people of Thamud, to whom Allah’s Prophet Salih was sent, were also inhabitants of an Arab region, and Allah’s wrath came upon them. Also, the people of Lut, who were the inhabitants of Sodom and Amoria (two places within the geographical boundaries of the Levant), were also destroyed there.

Nowadays and after those places have become urban areas, populated by people, there is nothing wrong in running various activities there.

Moreover, Sheikh Muhammed Nur Abdullah, President of the ISNA (Islamic Society of North America) and member of the Fiqh Council of North America, adds:

The dead sea food is allowed according to the Hadith where the Prophet (peace and blessings be upon him) was asked about the water of the sea, to which he said: “Its water is pure, and its dead meat is halal.”
So, any product produced from the dead sea is not haram. The same applies to anything in the sea like minerals and extracts.

In light of the above Fatwa, we conclude that there is nothing wrong in running that business in the Dead Sea region.
Also, there is nothing wrong in making the best use of the place in extracting certain materials for therapeutic purposes that are intended for conducting a halal business.