Which material is no longer permitted for laundry trays due to sanitary concerns?

Concrete is no longer permitted for laundry trays due to sanitary concerns primarily because it is porous and can harbor bacteria and other contaminants. The porous nature of concrete allows for the absorption of moisture and detergents, which can lead to the growth of mold and bacteria over time. This presents a health risk, especially when considered in the context of cleanliness and hygiene in laundry areas where clothing and linens are washed.

In contrast, materials like plastic and fiberglass are non-porous and easier to clean, making them more suitable for laundry use. Metal can also be cleaned effectively, but issues such as corrosion and rust can arise depending on the specific metal used. The change in regulations to exclude concrete reflects a shift toward materials that promote better sanitation and hygiene in environments that involve frequent contact with water and cleaning agents.