Phthalates in Caulks and Sealants

Published on April 14, 2023

Caulks and sealants play a crucial role in construction and building renovations, providing handypeople and homeowners with a means to seal windows, bathtubs, sinks, and other parts of their homes to close gaps and prevent water or air leakage. Unfortunately, these widely-used products often contain phthalates – hormone-disrupting chemicals associated with various health issues such as asthma, breast cancer, attention-deficit hyperactivity disorder (ADHD), obesity, and more. These harmful phthalates are not chemically bound to the caulk or sealant products, which means they can be released into the indoor air, household dust, our bodies, and the environment during both use and disposal, posing a hazard to our well-being.

The Ecology Center's Healthy Stuff Lab took action by conducting tests on 34 different caulks and sealants for phthalate content in partnership with Toxic Free Future. Carefully selecting products based on input from architects and builders on commonly used options and consumer availability, our findings showed that six tested products contained phthalates, raising concerns about the widespread presence of these harmful chemicals in everyday construction materials. Additionally, several products had alternative plasticizers (dibenzoate, alkylsulfonic phenyl ester, or DOTP), suggesting better alternatives are available.

Of the categories tested, the silane-modified polymers had the most phthalate products. Gorilla Heavy Duty Construction Adhesive also contained phthalates. Product types without phthalates included polyurethane and silicone sealants, though these products may contain other chemicals of concern. For a full list of products tested, view our test results below.

Healthy people live in healthy buildings, and healthy buildings must be made with healthy materials. Safer alternatives to phthalate-containing sealants exist, such as sodium silicate caulk and pre-compressed polyurethane joint seal. Join the Ecology Center and our partners at Toxic-Free Future in asking home improvement stores to only sell phthalate-free sealants.