Endocrine disruptors are chemicals that can interfere with endocrine (hormonal) systems. The endocrine system is a collection of glands in the body that produce hormones, regulating metabolism, growth, tissue function, sexual reproduction, and sleep, among other functions. Endocrine disruptors can include pesticides, metals, contaminants or food or chemicals commonly found in plastic. Exposure to these disruptors can happen through ingestion through food and water, as well as inhalation of particles in the air or through the skin. These can cause adverse effects, such as birth defects or cancerous tumours. The European Chemicals Agency (ECHA) declared Bisphenol A, a chemical found in many common plastics, as an endocrine disruptor.