Black slime bio-oils often bleed in to fabrics during the wash cycle. This contamination may affect skin and or scalp. Plus may cause spots in fabrics.
Detergents generally contain many VOC’s (agents that become fumes with moisture at room temperature). The most harmful may be benzine and 1,4-dioxane. These are highly cancerous and detrimental to the environment, plus they aid in washing machine build-up.
People regularly perspire in clothing, fabrics which are carrying invasive detergent chemicals. Secondly, people shower everyday and then having open pores, they grasp a towel laden with detergent and washer back-wash residue and spread it in to their skin.
Knowing this about detergents, may guide you to finding a true natural washing machine flush and detergent-free fabric cleaner.