物质群体是何时形成的？

物质群体是何时形成的？

When are substance groups formed?

作为候选名单编制的一部分，ECHA 会对这些物质进行分组。在将候选名单提交给 MSCA 之前，会对这些物质进行人工验证，但不会详细审查任何结构差异是否具有毒理学重要性。验证工作在 MSCA 的人工筛选过程中完成，这意味着在候选名单最终确定后，物质组的划分可能会发生变化。在某些情况下，分组可能仅适用于某些终点，而不适用于其他终点。最后，如果根据人工筛选结果认为有必要，并且积累的知识和不断加深的理解表明有必要采取更精确的分组方法，ECHA 和 MSCA 可能会对可能具有相同危险特性的其他物质进行第二次更精确的筛选。

ECHA forms groups as part of the shortlist compilation. The groups are manually verified before the shortlist is provided to MSCAs, but without examining in detail whether any differences in structures are toxicologically important. This is done during manual screening by MSCAs, which means that the group boundaries may be altered after the shortlist is finalised. On some occasions, the grouping may only hold for some endpoints and not for others. Finally, it is possible that ECHA and MSCAs carry out a second, more precise screening for additional substances that may have the same hazardous properties if based on the manual screening there is a need to do so and the accumulated knowledge and increased understanding indicates that a more precise grouping approach is warranted.