Use information on the history of harmonized classification
Classifying a substance: the importance of harmonized classification?

For substances harmonized before 2009 under the DSD and its APTs, harmonized classifications were generally discussed for all potential hazardous properties. All classifications and non-classifications were therefore applicable as they stood. Only certain substances (e.g. petroleum and hard coal derivatives) had a targeted classification and were assigned the note H (now deleted) to indicate the partial nature of the harmonized classification.

The history of harmonization can shed light on the scope of the discussions.

The ECHA website (follow: about the agency > Committee on Risk Assessment > Harmonised classification and Labelling ) provides minutes of meetings and opinions presenting harmonization recommendations.