**Preface to "Chemical and Biological Threats, Hazard Potential and Countermeasures"**

The scope of this special issue is to pay attention to various aspects of toxicology specifically focused on the chemical and biological threats, which may accidentally or on purpose endanger human health. Besides the characterization of such threats and their biological consequences we focus on the available and novel experimental countermeasures capable to protect from and/or treat such exposures. In particular, we have focused, in this special issue, on the neuroprotective approaches against organophosphorus poisoning, decontamination approaches against organophosphates and sulphur mustard. From a civilian sphere, we bring original reports describing occupational exposure risk to phthalates and diacetyl, commonly occurring plastic components and flavouring additive respectively and its health consequences. Finally, we present a review focused on micro and nanoplastics, their relation to human health and their exposure routes through the environment.

> **Jan Korabecny and Ondrej Soukup** *Editors*
