Download PDF Quartz or silica sand is often used as an extender in sealants to help with appearance, durability and resistance to dirt. How can this chemical affect my health? Acute (Short Term) Effects Toxic to Humans & Animals – Can be fatal on contact, ingestion or inhalation for humans and other mammals. Chronic (Long Term) Effects Cancer – Can cause or increase the risk of cancer. Other Health Effects – Can cause serious damage on contact or ingestion.