Is Perlite Toxic?

Hunker may earn compensation through affiliate links in this story.
One of expanded perlite's most striking features is its white color.

Perlite is a naturally occurring silicous rock and as such, is not toxic. Perlite is used in horticultural, construction and industrial applications. Ingesting the products that incorporate perlite may cause illness and, in excessive amounts, permanent harm or death.


Video of the Day

Horticultural Applications

Perlite is utilized as an ingredient in growing mixtures that contain no soil. The expanded rock provides aeration and moisture retention properties. Perlite has a neutral pH and is light weight, sterile and free of weeds. Perlite is also used as a carrier for fertilizer, herbicide and pesticide.

Construction Uses

Perlite is used as a loose-fill insulation in masonry construction due to its light weight and insulating properties. It is also used as an aggregate in concrete and gypsum plasters. Other construction applications include chimney linings, insulation under floors, ceiling tiles, roof insulation boards and paint.


Industrial Utilization

Perlite is utilized in an industrial setting for everything from filler for plastic to cement for geothermal, petroleum and water wells. Perlite is also used as a filter medium for chemicals, food products, pharmaceuticals and water. It is also used as an abrasive in soaps, cleaners and polishes.


Crude perlite contains up to 6 percent water. The water in the crude rock expands and pops when heated quickly, forming countless tiny holes. Expanded perlite can weigh as little as 2 lbs. per cubic foot.


Fun Facts

Perlite expands up to 20 times its original volume when heated to the right temperature. Perlite is mined and expanded all over the world, with the United States consuming and producing the most expanded perlite. Perlite is resistant to rot, rodents and termites.



Mary Schimenz Hopkins

Mary Schimenz Hopkins has freelanced for more than 20 years for such clients as Miller Brewing, Master Lock and local marketing agencies and hospitals. She has taught writing, worked as on-air personality for Milwaukee radio and served as fashion editor and columnist for a monthly magazine. Mary holds a Bachelor of Arts from Marquette University and a Bachelor of Arts from Mt. Mary College.