Glasslock · Food Storage Containers
GlassLock 5.4 Cup Oven Safe Round Container
Lower-concern choice, glass core is inherently PFAS-free; lid material status unclear but not flagged for treatment.
GlassLock containers are primarily borosilicate glass, which does not require PFAS-based coatings or treatments. The lid (likely polypropylene or silicone) is the unknown element, but food-contact plastics in sealed containers face less regulatory pressure than grease-resistant papers or waterproof textiles.
Shop Glasslock on Amazon →Material
borosilicate glass with plastic/silicone lid
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
Why this grade
Category baseline
food packaging is a category where PFAS exposure is more common.
No PFAS disclosure
No public statement about PFAS in this product.
Uncoated safe material
Bare, uncoated material (cast iron, stainless, carbon steel, or glass) with no surface treatment to contain PFAS.
The full breakdown
What it's made of and why it matters
The GlassLock 5.4 Cup container uses borosilicate glass, a heat-resistant silicate compound that does not leach into food under normal conditions. The lid combines plastic (likely polypropylene or polyethylene) with silicone gaskets for sealing. Borosilicate glass is chemically inert and free of BPA, phthalates, and PFAS in the glass portion itself; the lid materials present minimal documented leaching risk for food storage at room temperature or moderate heating.
The brand's record and disclosure
Glasslock does not publicly disclose detailed chemical composition or third-party testing results for lid materials on its website or packaging. The brand has no established recalls or safety controversies in major consumer databases. No certifications (BPA-free claims, FDA certifications) are prominently marketed, which is typical for glass container manufacturers who rely on material properties rather than additive transparency.
How it compares in its category
Borosilicate glass containers are among the safest options in the food storage category because the glass matrix itself is inert. This product is comparable to Pyrex and other glass storage lines. The main differentiation is the lid: Glasslock's silicone gasket design is standard for this category and does not introduce known hazards beyond those inherent to generic polypropylene or silicone.
If you buy it
Safe for oven and microwave use per label (up to stated temperature limits; verify before heating to high temperatures). Avoid subjecting the plastic lid to direct flame or prolonged high heat above 400F to prevent degradation. Inspect the silicone gasket annually for cracks, discoloration, or permanent deformation; replace the lid if damage occurs. Hand-wash or use the dishwasher according to manufacturer guidance; thermal shock (sudden temperature changes) can crack glass.
Beyond PFAS: other things we checked
Established hazard classes for this product type, assessed from public information. These never change the PFAS grade; a Likely flag caps the Verdict at “Buy with care.”
BPA/BPS in plastic lid
No publicly available test data or manufacturer disclosure confirms presence of BPA or BPS in Glasslock lids. Polypropylene and polyethylene are not typically formulated with these chemicals, though some generic plastics may contain residual compounds; the lid is not in direct contact with hot liquids during storage.
Phthalates in silicone gasket
Silicone gaskets are not a known source of phthalates in food storage applications. No safety alerts or test reports have flagged Glasslock lids for phthalate leaching. Silicone is chemically stable and commonly used in food-contact seals.
Microplastics from lid degradation
Repeated heating, cooling, and dishwasher cycles can gradually degrade plastic and silicone components. Over years of heavy use, microscopic particles may shed into food, particularly if the lid is heated above its design temperature. This is a general risk for all plastic-lidded containers, not specific to Glasslock.
Lead or cadmium in glass
Borosilicate glass used in food storage does not intentionally contain lead or cadmium. No recalls or safety reports have documented contamination in Glasslock products. Glass of this type is stable and does not leach heavy metals into stored food.
Off-gassing or VOC release from lid materials
Polypropylene and silicone have minimal volatile organic compound emissions at room temperature. No odor or off-gassing complaints are documented for Glasslock containers during normal storage use. Risk increases only if lids are subjected to prolonged high heat.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 82% confidence. It is not a lab result.
No independent PFAS lab test is on record for this exact product. A lab test could move the score in either direction.
The brand has not made a specific, verifiable PFAS-free statement, so part of this score reflects that missing disclosure rather than a confirmed material.
Formulations and coatings change between production runs. Always check the current label before buying.
Safer alternatives in Food Storage Containers
Caraway
Food Storage Set
Glass containers with plastic lids
Lower concern; glass + plastic lids with stated PFAS-free position, but no third-party verification of lid material.
⚠Risky category by default
Caraway
Home 9-Piece Mini Food Storage Set
Borosilicate glass containers with plastic lids
Lower-concern option; glass containers avoid PFAS coatings, but verify lid material before purchase.
⚠Risky category by default
Caraway
Cream 6.6-Cup Non-Stick Glass Food Storage Container with Lid
borosilicate glass with non-PFAS lid
Lower PFAS concern, glass container with stated non-PFAS lid, though third-party verification absent.
⚠Risky category by default
More food storage containers grades
How we score: every product runs through the same public 0–100 rubric based on materials, coatings, brand disclosure, lab findings, and recalls. See the full methodology → Spotted a mistake? Report an error.