One of the substances that the European Union (EU) is proposing to ban is hexavalent chrome. This substance is present in the surface finishes of some Lansing parts. These parts can be placed in four sub-categories:
Sub-category 1: Aluminum parts (sheet and extrusion) with a clear Iridite finish:
Iridite is a very thin layer of hexavalent chrome. In the worst case, hexavalent chrome is present in the range of 26-62 parts per million (PPM) by weight. All PPM calculations are documented below.
Sub-category 2: Vinyl-clad aluminum parts:
The aluminum surfaces are prefinished with Iridite prior to cladding. Excluding vinyl, hexavalent chrome is present in the range of 26-62 PPM by weight.
Sub-category 3: Vinyl-clad steel parts:
The surfaces are treated with hexavalent chrome prior to vinyl-cladding (exterior surface) and painting (interior surface). Excluding the vinyl and paint, hexavalent chrome is present in the range of 14-33 PPM by weight.
Sub-category 4: Aluminum parts (sheet and extrusion) with powder coat paint finish:
The aluminum surfaces are prefinished with Iridite prior to powder coat painting. In the worst case, hexavalent chrome is present in the range of 26-62 PPM by weight (excluding powder coat paint).
The question as to whether or not these parts are RoHS compliant lies in the interpretation of what the European Union means by a "homogeneous material". In a homogeneous material, hexavalent chrome cannot exceed 0.1% by weight (1000 PPM by weight). As noted above, all Lansing parts in question fall well under this limit.
The term “homogeneous” does not appear in the original RoHS Directive. It first appears in December 2003 in a Commission stakeholder document. The purpose of this document was to propose maximum concentration values for RoHS restricted substances:
“A maximum concentration value of 0.1% by weight in homogeneous materials for lead, mercury, hexavalent chromium, polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE) and of 0.01% weight in homogeneous materials for cadmium shall be tolerated. Homogeneous material means a unit that can not be mechanically disjointed in single materials”.
Liberal interpretation: Under this guideline for homogeneous materials ("can't be mechanically disjointed"), these parts can be interpreted to be homogeneous and, hence, to be RoHS-compliant, since hexavalent chrome content is far less than 1000 PPM by weight. A Commission Amendment to the RoHS Directive, dated 18 Aug 2005, appears to support this interpretation. It states,
“... a maximum concentration value of 0,1 % by weight in homogeneous materials for lead, mercury, hexavalent chromium, polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE) and of 0,01 % by weight in homogeneous materials for cadmium shall be tolerated.”
This decision reiterates the percentage by weight concept and leaves open to interpretation the meaning of “homogeneous”. It is believed to be the result of lobbying efforts for "homogeneous" to be interpreted as "grind up the whole and analyze the resulting powder".
Conservative interpretation: The UK government has suggested (not decreed) that the term “homogeneous” be understood as being “of uniform composition throughout”. Under this interpretation, metals and their coatings would be considered to be of multiple homogeneous materials (e.g., aluminum and Iridite are two separate homogeneous materials) even though they cannot be "mechanically disjointed". Should the EU adopt this guideline, then these parts would be interpreted not to be RoHS-compliant.
This confusion is further aggravated by the lack of any standards against which materials are to be tested. In addition, persistent rumors have been floated that hexavalent chrome passivation coatings are going to be exempted from RoHS. Note further that the EU Commission has employed consultants to independently review outstanding exemption requests. At a February 15th meeting, those consultants recommended that hexavalent chrome passivation coatings be exempted, at least on a time-limited basis. As yet, the EU has not taken action, pro or con, on the recommendation.
At this point, we simply do not know with any certainty whether or not parts with Iridited surface finishes comply. Hence, Lansing cannot issue Certificates of Compliance for parts within these groups until the EU has established clear definitions and the appropriate standards against which products are going to be tested. In the interim, we will freely share any relevant information with regard to materials, finishes, etc.