Marie, The environmental laws in California are most definately strict. It is not out of the ordinary to see limits of copper discharge as low as .4ppm. As the laws have become more and more strict the PCB manufactures have been able to stay in compliance. Surprisingly many PCB shops have found themselves not only saving money and reducing waste in the process, but also streamlining their waste treat systems. If you would like some information on the systems and types of chemicals used feel free to contact me anytime. Stephen M. Wentz Florida CirTech Inc. VM#(408)233-0443 PH#(408)996-2959 ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ##############################################################