None of the particulate copper systems have been submitted to the American Wood Protection Association (AWPA) for evaluation; thus, the particulate systems should not be used in applications where AWPA standards are required. However, all of the particulate copper systems have been tested and approved for building code requirements by the International Code Council (ICC). The particulate copper systems provide a lighter color than dissolved copper systems such as ACQ or copper azole. Proponents of the micronized copper systems claim that the systems are subject to third party inspection under a quality monitor program. However, the monitoring program is not subject to oversight by the American Lumber Standards Committee (ALSC) as is required for the AWPA standard systems. Two particulate copper systems, one marketed as MicroPro and the other as Wolmanized using μCA-C formulation, have achieved Environmentally Preferable Product (EPP) certification. The "EPP" certification was issued by Scientific Certifications Systems (SCS) and is based on a comparative life-cycle impact assessments with an industry standard. The copper particle size used in the "micronized" copper beads ranges from 1 to 700 nm with an average under 300 nm. Larger particles (such as actual micron-scale particles) of copper do not adequately penetrate the wood cell walls. These micronized preservatives use nano particles of copper oxide or copper carbonate, for which there are alleged safety concerns. An environmental group has recently petitioned EPA to revoke the registration of the micronized copper products, citing safety issues. Alkaline copper quaternary (ACQ) is a preservative made of copper, a fungicide, and a quaternary ammonium compound (quat) like didecyl dimethyl ammonium chloride, an insecticide which also augments the fungicidal treatment. ACQ has come into wide use in the US, Europe, Japan and Australia following restrictions on CCA. Its use is governed by national and international standards, which determine the volume of preservative uptake required for a specific timber end use. Since it contains high levels of copper, ACQ-treated timber is five times more corrosive to common steel. It is necessary to use fasteners meeting or exceeding requirements for ASTM A 153 Class D, such as ceramic-coated, as mere galvanized and even common grades of stainless steel corrode. The U.S. began mandating the use of non-arsenic containing wood preservatives for virtually all residential use timber in 2004.