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Final Decision to Certify Hazardous Waste Environmental Technologies

Airco Coating Technology
Airco Coating Technology’s Surface Treatment System

Published Weekly by the Office of Administrative Law
Register 95, No. 35-Z
September 1, 1995
pp 1411-1415

The California Environmental Protection Agency, Department of Toxic Substances Control (DTSC) has made a final decision to certify the following company’s hazardous waste environmental technology listed below:

Airco Coating Technology
4020 Pike Lane
Concord, CA 94524

Airco Coating Technology is a manufacturer of cold gas plasma systems for surface cleaning of various plastic and stainless steel parts, and altering the surface chemistry of various plastic parts.

Chapter 412, Section 25200.1.5., Health and Safety Code, enacted by Assembly Bill 2060 (AB 2060 by Assemblyman Ted Weggeland, 1993), authorizes the DTSC to certify hazardous waste environmental technologies. Only technologies that are determined to not pose a significant potential hazard to the public health and safety or to the environment when used under specified operating conditions and which can be operated without specialized training and with minimal maintenance may be certified. Incineration technologies are explicitly excluded from the certification program.

The purpose of the certification program is to provide an in-depth, independent review of technologies at the manufacturers’ level to facilitate regulatory and end-user acceptance and to promote and foster growth of California’s environmental technology industry.

DTSC makes no express or implied warranties as to the performance of the manufacturer’s product or equipment. The end-user is solely responsible for complying with the applicable federal, state, and local regulatory requirements. Certification does not limit DTSC’s authority to require additional measures for protection of public health and the environment.

By accepting certification, the manufacturer assumes, for the duration of certification, responsibility for maintaining the quality of the manufactured equipment and materials at a level equal to or better than was provided to obtain certification and agrees to be subject to quality monitoring by DTSC as required by the statute under which certification is granted.

DTSC’s proposed decision to certify has been previously noticed on July 21, 1995, in the California Regulatory Notice Register 95, Volume No. 29-Z, pp. 1163-1167. Written comments in relation to the proposed certification received during the public review and comment period have been duly considered in the final certification as presented here. DTSC’s final certification shall be effective on Monday, October 2, 1995.

Additional information supporting DTSC’s final certification decisions is available for review at:

California Environmental Protection Agency
Department of Toxic Substances Control
Office of Pollution Prevention and Technology Development
P.O. Box 806
301 Capitol Mall, 1st Floor
Sacramento, California 95812-0806
(916) 322-3670

A description of the technology to be certified, the final certification statement and the certification limitations for the technologies of each of the companies listed above follows.




Airco Coating Technology
Surface Treatment Systems.


Airoc Coating Technology

Technology Description

Airco Coating Technology (ACT), a division of the BOC Group, Inc., manufactures the PSO350, PSO500, and Hammer II cold gas plasma systems for surface cleaning of various plastic and metallic parts, and altering the surface chemistry of various plastic parts. As a Pollution Prevention technology, these systems are used to replace solvent based systems for surface cleaning or treatment of parts thereby reducing or eliminating the generation of hazardous waste and/or toxic air emissions associated with the use of solvents.

Gas plasma technology is a process where common or inert gases such as air, oxygen, helium and argon are partially ionized by radio frequency (RF) energy to create a plasma at close to ambient temperatures. Plasma is a partially ionized gas containing ions, electrons, and various neutral species. Each process gas used produces a unique plasma chemistry. The plasma contains highly reactive positive and negative ions and free radicals that react with organic contaminants or organic polymers (i.e., plastics). The complete systems as manufactured by Airco include a process controller, a reactor chamber, and RF generator, an automatic impedance matching system, a vacuum pump, and a gas control module. Parts to be cleaned or treated are placed in the reactor, a vacuum chamber, in a batch operation. Low flow rates of the selected process gas are subjected to RF energy to create a plasma within the reactor. Process gas flow rates vary depending on the specific system, ranging from less than 1 liter/minute for the PSO350 and PS0500, and up to 10 liters/minute for the Hammer II. The gas plasma within the reactor is maintained at near ambient temperature (bulk gas temperature) and maintained under vacuum conditions (e.g., 100 to 500 millitorr). The gas plasma reacts with the organic surface contaminants or plastic surface materials of the parts being treated. Ionized gases recombine to their original gas form as they exit the reactor along with reaction products formed during the treatment process.

Process gas composition, pressure and flow rate, and parts residence time are the critical parameters controlled for each specific applications. The physics and chemical reactions occurring in plasmas are very complex and not fully understood. Depending on the process gas used and the composition of the part being treated, various chemical reactions can occur with resulting off-gas emissions. Reaction products in the emissions can potentially be toxic, corrosive, or flammable. However, because of the low process gas flow rates for these systems, the relative volumes of these contaminants are small and can be controlled. Depending on the specific applications, the emissions generated by the plasma process may require controls to capture or treat contaminants of concern to an acceptable level.

ACT Surface Treatment Systems can be used to remove organic surface contamination from surfaces of plastic and metal parts, or to modify or enhance the physical and chemical characteristics of the surface of polyester and polypropylene plastic parts to improve their bonding and adhesion properties. After plasma treatment, plastics typically can be bonded, coated or painted without the use of toxic, solvent-based cleaning processes. In certain cases, the chemistry of the plastic surface is modified or enhanced to allow the plastic part to be painted or coated without an adhesion promoter pre-coating.

Certification Statement

Under the authority of Section 25200.1.5 of the California Health and Safety Code, DTSC hereby certifies the PS0350, PS0500, and Hammer II Surface Treatment Systems manufactured by Airco Coating Technology as a Pollution Prevention technology when installed, operated, monitored, and maintained according to Airco’s standards and specifications. The pollution prevention certification is specific to the above systems using process gas flow rates less than 10 liters/minute with air, oxygen, helium or argon as the process gas and applied to polyester and polypropylene plastics, silicone, or stainless steel. By using the plasma treatment end-users can avoid the hazardous waste generation and toxic air emissions that result from solvent-based processes.

The use of several volatile organic compounds (VOCs) has been documented to be eliminated through application of ACT Surface Treatment Systems. These chemicals include Freon, 1,1,1- trichloroethane (1,1,1 TCA), dimethyl formamide, ethanol, a xylene-based adhesion promoter, and several VOC-based adhesion promoters and primers. The processes replaced or avoided through use of the ACT Surface Treatment Systems included a Freon cold solvent cleaning system, an ethanol cold solvent cleaning system, various manual methods of solvent cleaning parts, and solvent cleaning of adhesion promoter spray equipment. The hazardous waste environmental benefit gained from use of this technology is the avoidance of solvent-based surface cleaning systems which generate spent solvents and sludges requiring recycling, treatment or disposal. The largest environmental benefit, which indirectly relates to the hazardous waste certification, is the elimination of toxic air emissions typically associated with solvent-based cleaning systems.

Limitations of Certifications

DTSC makes no express or implied warranties as to the performance of the ACT’s Surface Treatment System. DTSC has not conducted any bench or field tests to confirm the manufacturer’s performance data. Nor does DTSC warrant that the ACT Surface Treatment System is free from any defects in workmanship or material caused by negligence, misuse, accident or other causes.

DTSC believes, however, that the plasma-based ACT Surface Treatment System can replace solvent-based processes to remove contamination from materials or to prepare the surface of materials for bonding, coating or painting, subject to the certification statement when the ACT Surface Treatment System is used in accordance with manufacturer’s specifications. Said belief is based on the review of the data submitted by the manufacturer and other information, and is based on the use of the product in accordance with the manufacturer’s specifications.

Specific Conditions

The certification is strictly limited to the pollution prevention achieved through use of ACT Surface Treatment Systems for the process gases, process gas flowrates, and materials specified in the above Certification Statement. The certification makes no claims concerning the performance or effectiveness of ACT Surface Treatment Systems to clean, treat, or prepare parts or materials prior to bonding, coating or painting.

DTSC does not know all the possible combinations of process gases and materials and potential contaminants to which the technology may be applied, nor does DTSC know all of the performance specifications required by end-users. Achieving performance specifications involves many variables including the material to be cleaned, the type and amount of contamination, the cleanliness level required, the size and shape of the parts to be cleaned, etc. These factors all affect the potential pollution prevention benefit that may be realized from use of an ACT Surface Treatment System. Potential end-users must examine their individual processes and product specifications, and work with ACT to evaluate and determine whether an ACT Surface Treatment System can meet the end-user’s performance specifications and, if so, what emission controls may be required.

This certification is contingent on the use of this technology with proper air monitoring and emission controls. DTSC did not evaluate the hazard associated with the air emissions from this system. The end-user is ultimately responsible for determining the suitability of the ACT Surface Treatment System for their specific applications and for complying with the applicable Federal, State, Air Quality Management District (AQMD) and local regulatory requirements. Toxic gases may be produced and need to be controlled.

For each specific application, the end-user must ensure compliance with all applicable worker health and safety standards established by OSHA, Cal/OSHA, and other state and local agencies.

Basis for Certification

The main emphasis of the evaluation was to verify that the ACT Surface Treatment System could substitute for solvent-based cleaning and thereby eliminate or reduce the generation of hazardous wastes (i.e., hazardous waste pollution prevention). Additionally, the evaluation documented the reductions in solvent usage and associated air emissions, major environmental benefits through use of the technology. The evaluation focused on gathering data and information from end-users of the technology who had realized hazardous waste pollution prevention benefits through implementation of the technology.

Background information and technical literature in support of the technology as a process substitute for solvent-based surface cleaning systems was obtained from a variety of sources, including journal articles, industry experts, professional associations, emission testing reports, trade magazine articles, Senate Bill 14 (SB 14) Hazardous Waste Source Reduction Plans, air quality management districts, and end-users.

DTSC contacted twelve (12) end-users of the technology to obtain data to document and quantify the amount of pollution prevention realized through use of the technology. All twelve end-users contacted were very satisfied with the ACT Surface Treatment Systems. Quantifying the amount of pollution prevention achieved by the end-users was more difficult than envisioned at the outset of the certification evaluation. Many factors contributed to the difficulties in documenting or quantifying the pollution prevention achieved. Environmental accounting procedures of the surveyed companies were not able to segregate the amount of hazardous waste generated by individual unit processes. The overall solvent usages generally had to be estimated from purchasing records which in some cases were combined for different process lines requiring the same solvents. Many end-users manifested large waste streams from multiple operations and were unable to discern their waste stream reduction due to the ACT system. Many end-users contacted did not create or maintain internal records or documents that identified specific processes and waste streams that were affected by the implementation of the ACT system. Several end-users contacted had multiple plasma systems, some of which were manufactured by competitors. Many end-users contacted implemented their ACT system from three to six years ago, and have undergone company reorganizations, layoffs, and plant relocations since implementing their ACT system. Manifest information reviewed frequently composited the same waste types generated by multiple or different process lines within the same company. For this reason, heavy reliance had to be placed on personal communications with the end-users, either managers or engineers involved in the specific manufacturing process, or environmental officers of the companies responsible for preparation of the SB 14 Hazardous Waste Source Reduction Plans.

For each end-user surveyed, DTSC identified the plasma system model used, the process gas, the material(s) processed, the solvent-based cleaning process replaced or avoided through use of the ACT Surface Treatment System, the type and amount of hazardous waste reduced or eliminated, the amount of solvent used and associated air emissions prevented, and how long the technology has been in operation. The major environmental benefit of the ACT Surface Treatment Systems was found to be the reduction in solvent usage and associated reduction in air emissions of VOCs, particularly Freon. The amount of hazardous waste generation reduced or eliminated ranged from a few lbs/yr of chlorofluorocarbons (CFCs) to 500 gal/day of ethanol. Hazardous waste generation eliminated by end-users included F005 solvent waste containing toluene and xylene; Freon; MEK; ethanol; and 1,1,1, TCA.

To compare ACT end-users’ processes and waste streams to other similar processes in industry, DTSC reviewed twenty-eight SB 14 Hazardous Waste Source Reduction Plans. The SB 14 plans were submitted to DTSC from a variety of industries, including the aerospace, metal finishing, petroleum, semiconductor, and plastics and resins industries. Five companies were contacted which identified industrial unit processes in their SB 14 plans which were similar to those of the twelve ACT end-users surveyed. An effort was made to determine a hazardous generation rate for the unit processes which were replaced by the plasma cleaning technology. The review of the SB 14 plans documented that processes similar to the ACT end-users do produce hazardous waste. Data was not available, however, to generically quantify the hazardous waste generation rates for any of the unit processes investigated.

Four industry associations were contacted for information on solvent cleaning processes in an effort to determine and “industry average” of solvent required to clean parts and an “industry average” of the hazardous waste generated by solvent cleaning processes. The four associations contacted were 1) the Halogenated Solvent Industry Association, 2) the National Association of Metal Finishers, 3) the Society of Manufacturing Engineers, and 4) the Semiconductor Equipment and Materials International (SEMI). Due to the multitude of variables that affect solvent usage and hazardous waste generated by the solvent cleaning process, the four associations contacted were unable to provide DTSC with an “industry average” of solvent usage required to clean parts, or an “industry average” of hazardous waste generated from solvent cleaning. The variables include the material to be cleaned, the material’s type and amount of contamination, the cleanliness level required, the size and shape of the parts to be cleaned, the type of solvent, the solvent temperature, and others.

Industry experts were contacted and provided information on the type and amount of emissions that could be produced by the plasma process. Plasma surface treating processes can produce air emissions which are toxic, reactive, ignitable, corrosive, mutagenic, or carcinogenic depending on the application, material material contamination, process gas, and process conditions. For this reason each prospective end-user must evaluate their specific application to determine what specific control equipment, if any, is required to capture, treat, or destroy process air emissions.

Himont Plasma Science (now Airco Coating Technology) contracted with Brown and Caldwell Consultants, a California laboratory certified by the California Air Resources Board, for testing air emissions, to conduct an independent evaluation of emissions from several ACT Surface Treatment Systems. Brown and Caldwell tested the PS0350, PS0500, and Hammer II units at two different power settings and with various process gases. The PS0350 and PS0500 were tested at 200 and 500 watts power settings with O2, air, nitrous oxide (N2O), and O2/CF4 process gases at a flow rate of 2 liters/minute. The Hammer II was tested at 1,000 and 2,500 watts with 02 and air at a flow rate of 10 liters/minute. The results of the testing demonstrated low emissions of NOx, CO, and THC. The maximum emissions determined from the testing were for the Hammer II system operating at 2,500 watts using 10 liters/minute of air oxygen as the process gas: 0.0021 lbs./hr. (0.95 g/hr.) of NOx, 0.01 lbs./hr. (4.5 g/hr.) of CO, and 0.000023 lbs./hr. (0.01 g/hr.) of THC.

The volume of emissions from the ACT systems are typically low, due to the flow rate of process gas. Process gas flowrates provided by three end-users were: 0.25 liters/minute (oxygen); 0.3 liters/minute (air); and 0.8 liters/minute (argon). These flow rates are below the Brown and Caldwell reported test flow rates of 2 liters/minute. Since a small percentage of process gas is reacted by the RF energy (typically 2-5%), the majority of the emissions consist of unreacted process gas.

The Bay Area Air Quality Management District, the South Coast Air Quality Management District, and the Sacramento Area Air Quality Management District were consulted on their regulated criteria pollutants and respective threshold limits. AQMDs only regulate emissions when mass emission rates exceed their established threshold limits for regulated air pollutants. Two of the AQMDs contacted stated that plasma surface treatment systems typically did not exceed their established threshold limits due to the low flowrates involved, and that they were not concerned with their emissions. The Brown and Caldwell emissions testing results indicated emissions below the criteria for NOx and CO for the machine and process gas flow rates tested.

In addition, DTSC reviewed the “Facility Standards and Safety Guidelines, 1993” developed by SEMI. SEMI F5-90, “Guide for Gaseous Effluent Handling”, provides information regarding potential emissions of plasma cleaning and the available emission control systems.

Recommended Applications of the Treatment System

Due to the highly varied applications and the wide variety of process gases, materials, and material contamination, DTSC makes no specific recommendations regarding the application of the ACT Surface Treatment System. DTSC recommends potential end-users contact the manufacturer for suitability for their specific application.

Regulatory Implications

DTSC’s certification is based on the technology’s performance and by itself does not change the regulatory statues of gas plasma surface treatment systems; it should, however, facilitate and encourage the acceptance of this technology for surface cleaning or treatment of parts thereby reducing or eliminating the generation of hazardous waste and/or toxic emissions associated with the use of solvents.

This Certification is issued as part of a pilot project to expedite the California Environmental Technology Certification Program. As a result, this Certification is subject to the conditions set out in the regulations to be developed, such as the duration of the Certification, the continued monitoring and oversight requirements, and the procedures for certification amendments, including decertification.

By accepting this Certification, the manufacturer assumes, for the duration of the Certification, responsibility for maintaining the quality of the manufactured materials and equipment at a level equal or better than was provided to obtain this certification and agrees to be subject to quality monitoring by DTSC as required by the law, under which this Certification is granted.

For more information, contact us at:

Department of Toxic Substances Control
Office of Pollution Prevention and Technology Development
P.O. Box 806
Sacramento, California 95812-0806
Phone: (916) 322-3670
Fax: (916) 327-4494

File last updated: October 9, 1996