Sigma Review, Is Sigma Non-Toxic?
Across 8 graded products, Sigma averages Good (72/100). On disclosure, the brand says nothing publicly about PFAS. 5 of its products grade Good or better. Grades are model-based estimates, not lab results.
PFAS Authority is a scoring system, not a laboratory. We do not test products ourselves. Grades are model-based, built from published ingredients, materials, certifications, brand disclosures and third-party lab results where they exist. See the rubric.
Does Sigma have PFAS, by category
Worth buying from Sigma Good or better, best-graded first
Sigma
WR Protector Filter
Fiberglass filter media with cellulose
Fiberglass fiber shedding
Fiberglass filters can release microscopic fibers during handling, installation, or if…
Microbial biofilm growth in housing
If the filter housing is not drained between uses or is stored with standing water…
Bacterial colonization if unused
If a saturated cartridge is left in the housing without water flowing through it for…
No known PFAS risk. Brand silent on composition.
⚠Brand says nothing about PFAS
Sigma
46mm WR Protector Filter
glass optical element with metal frame
WR hydrophobic coating degradation
The water-repellent layer may degrade over 5-10 years with repeated cleaning or UV…
Lower concern optical filter; no identified PFAS risk factors.
⚠Brand says nothing about PFAS
Sigma
58mm WR Protector Filter
Optical glass, aluminum frame, non-coated optical surfaces
Optical glass fragility and sharp edges
If dropped or cracked, borosilicate glass can fracture and create sharp edges. This is a…
Lower concern. Optical glass and aluminum have minimal PFAS risk.
⚠Brand says nothing about PFAS
Sigma
WR UV Filter
UV-absorbing optical glass or mineral coating
Optical coating degradation and microabrasion
The WR hydrophobic and anti-reflection coatings will degrade with use and improper…
Lower concern optical filter; no known PFAS-prone components identified.
⚠Brand says nothing about PFAS
Sigma
Protector Filter
Unspecified filter media
Undisclosed filter media composition
Without public specification of active ingredients (carbon type, resin, binders, or…
Bacterial growth if maintenance neglected
Any water filter housing can harbor bacteria and mold if cartridges are not replaced on…
Cartridge/filter media shedding into water
Degraded carbon particles or fiberglass fibers can migrate into filtered water if the…
PFAS
PFAS compounds are used in some filter media binders and Teflon-family coating coatings…
Insufficient public data.
⚠Brand says nothing about PFAS
Graded and flagged Poor and Bad, we’d swap these
Sigma
95mm WR Protector Filter
Optical glass with unspecified multi-coatings
Multi-coat composition uncertainty
Sigma does not disclose the chemical identity of anti-reflective and water-resistant…
Coating details withheld.
⚠Undisclosed proprietary coating
Sigma
WR UV Filter SIGMA Corporation
UV filter composition unspecified
Undisclosed active ingredient toxicity (organic UV absorbers)
If this is a cosmetic UV filter using organic absorbers like avobenzone or oxybenzone…
PFAS
If WR UV Filter is a water or industrial filtration product, PFAS-based binders or…
Preservative or stabilizer allergens or irritants
UV filters require preservatives and chemical stabilizers to prevent degradation; without…
Material coating degradation with environmental exposure
If used as a window film or optical coating, UV filter resins can yellow, crack, or leach…
Details too sparse for PFAS risk assessment.
⚠Undisclosed proprietary coating
Sigma
WR CPL Circular Polarizer Filter
Optical glass, aluminum frame, likely multi-coated lens elements
Glass breakage and sharp edges
Drops or impacts can shatter the filter glass, creating sharp fragments. Risk is…
Lower concern. Optical filters rarely require PFAS; brand does not comment.
⚠Undisclosed proprietary coating
Sigma and PFAS, common questions
- Does Sigma have PFAS?
- We graded 8 Sigma products, averaging Good (72/100). 5 grade Good or better. Grades are model-based estimates built from published materials, ingredients and disclosures, not lab tests.
- Is Sigma non-toxic?
- Sigma WR Protector Filter is the highest-graded Sigma product we have scored, at 85/100. It depends on the product line rather than the brand, so check the grade of the exact item you are buying.
- Which Sigma products are lower concern for PFAS?
- The highest-graded Sigma products we have scored are Sigma WR Protector Filter, Sigma 46mm WR Protector Filter, Sigma 58mm WR Protector Filter. That is our model-based estimate from materials and public disclosure, not a lab test.
- Which Sigma products should I avoid?
- The lowest-graded Sigma products we have scored are Sigma WR CPL Circular Polarizer Filter, WR UV Filter SIGMA Corporation, Sigma 95mm WR Protector Filter. Each one links to the evidence behind its grade.
Every grade uses the same public rubric. How grades work →