Bar soap is better for the environment than liquid body wash and poses no health risk to the general population.
The switch from bar soap to liquid has been driven by a fear of bacteria lurking on bar soap. Companies encouraged the notion that using liquid soap was more hygienic. This NY Times article which asked "Does each member of the family need an individual bar of soap to prevent spreading germs, or do we have to switch to liquid soap?" came to a very different conclusion. It cites studies that concluded washing even with contaminated bar soap is unlikely to transfer bacteria, especially if the bar gets rinsed off between uses. "These findings, along with other published reports, show that little hazard exists in routine handwashing with previously used soap bars and support the frequent use of soap and water for handwashing." So how can a bar of soap have bacteria on it and yet not spread germs? Simply, washing is a two step process. This leads us to the next question "If liquid soaps provide no hygiene benefit, why have companies been so aggressive in marketing liquid body washes?" This article on US website DailyFinance may provide a clue.
Their comparison showed bathing with the recommended amount of Olay body wash cost HK$1.33 per wash while bathing with Ivory bar soap cost just over HK$0.09, providing a significant profit motive for companies to get us to switch. While a complaint against bar soap is that it may be harsh and drying. There are many varieties of bar soaps in the market that contain glycerine and natural oils that moisturize the skin. These soap can be just as gentle and mild on the skin, negating any advantage of body washes. Containing lots of water, body washes are also much heavier than bar soap, resulting in a significantly higher carbon footprint for transportation. Bar soap has a clear edge in transportation, packaging and disposal. Most liquid body washes are made of petroleum, while many traditional bar soaps are made of saponified animal fat and plant oils. Liquid soaps need the addition of emulsifying agents and stabilizers to maintain their consistency.