The phrase "high levels of the chemical" refers to a situation where there is an excessive amount or concentration of a particular chemical substance present in something. It could be in the environment, such as water, air, soil or food, or it could refer to the presence of the chemical in a person's body, such as blood or urine samples. High levels of a chemical can indicate potential harm to humans, animals, plants or the ecosystem and may require immediate action to reduce exposure or mitigate any negative effects.