Xylene is classified as moderately hazardous, Category A; should it be labeled as toxic or flammable?

They are classified as flammable or toxic. For flammable substances, the LEL value is determined in accordance with GB50493; for toxic substances, the maximum allowable concentration MAC, the time-weighted average allowable concentration PC-TWA, the permissible concentration for short-term exposure PC-STEL, and the immediately dangerous to life and health concentration IDLH are determined using standards such as GBZ2.1, GBZ223, and the Catalogue of Highly Toxic Substances, HG20660. First, compare which of MAC, PC-TWA, and PC-STEL is the smallest value; that value will be used as the occupational exposure limit OEL. Next, check whether the accuracy and lower range of the measuring instrument you have chosen are sufficient to meet the OEL value. If they are sufficient, then that value can be used; otherwise, 5% of the IDLH value should be used as the OEL. Finally, compare the 100% OEL with the 25% LEL; take the smaller of the two values, and this value will be the primary alarm threshold you need to set. Xylene is considered toxic; the first-level alarm threshold is set at 22 ppm, and the second-level alarm threshold is 45 ppm