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Final Decision to Certify Hazardous Waste Environmental Technology


Batch chemical treatment process designed to treat aqueous formaldehyde wastes

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

The SCIGEN NEUTRALEX technology for treating formaldehyde in waste neutral buffered Formalin from histopathology specimen preservation and use of automated histopathology tissue processors.


333 East Gardena Blvd.
Gardena, CA 90249

Chapter 412, Statutes of 1993, Section 25200.1.5, Health and Safety Code, enacted by Assembly Bill 2060 (AB 2060 by Assemblyman Ted Weggeland) authorizes DTSC to certify the performance of hazardous waste environmental technologies. Only technologies which 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 independent technical evaluation of technologies to identify those meeting applicable quality standards, so as 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 and their operation 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 notice of intent to certify was published on April 18, 1997 in the California Regulatory Notice Register 97, Volume No. 16-Z, pp. 846-852. 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 become effective on June 29, 1997.

Additional information supporting DTSC's final decision, including the DTSC technology certification evaluation report, are available for review. Requests for additional information or comments concerning this decision should be submitted to the following address:

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, CA 95812-0806
Attn: Dr. Bruce La Belle (916) 324-2958

A description of the technology to be certified, the certification statement, and the certification conditions and limitations follows.





SCIGEN NEUTRALEX Technology for Treatment of Aqueous Formaldehyde Wastes From the Health Care Industry

SCIGEN, Inc.; Gardena, California

Technology Description

The patented SCIGEN NEUTRALEX technology is a batch chemical treatment process designed to treat aqueous formaldehyde wastes. The technology is based on the reaction of formaldehyde with a sulfuric reducing agent. This certification evaluation is specific to its use for treating the formaldehyde in waste 10% neutral buffered Formalin. (10% NBF) from histopathology tissue specimen preservation and from the operation of automated histopathology tissue processors. The technology consists of:

  • NEUTRALEX reagents as a powder prepackaged in a foil packet. The currently available packets are designed to contain sufficient ingredients to treat one gallon of 10% NBF waste per packet.
  • A container in which the reagents are mixed with the waste Formalin; SCIGEN supplies a five-gallon container, but other suitable containers may be used.
  • Instructions for the proper use of the technology.
  • A Material Safety Data Sheet (MSDS).
  • A master copy of a log sheet for recording the results of each batch treatment.

Formaldehyde is commonly prepared in industry as approximately a 37% aqueous solution by weight. This formaldehyde solution is referred to as Formalin (formerly trademarked). Commercial formulations sold and used in the health care industry are typically prepared by the tenfold dilution of Formalin along with the addition of buffers to maintain a neutral pH and 1.0-1.5% methanol to stabilize the formaldehyde. It is referred to as "10% neutral buffered Formalin (10% NBF)." 10% NBF contains approximately 3.7% formaldehyde by weight. The amount of 10% NBF waste generated at a health care facility typically ranges from a few gallons per week to a few gallons per day. Formaldehyde is toxic to humans and other species by ingestion, inhalation, and other exposure routes. Practices for managing 10% NBF waste include shipment off-site as a hazardous waste, on-site treatment, or disposal to sewer (where legal). SCIGEN's NEUTRALEX technology is intended to provide a safe and effective option for on-site treatment of these wastes.

After removal of any residual tissue from the waste by filtration with an 80-mesh or smaller filter, the waste is placed into the reaction container. For each gallon of waste to be treated, one packet of NEUTRALEX is opened and its contents poured into the reaction container. The container is closed, stirred, and allowed to stand for 15 minutes while the reaction occurs. After being tested with an appropriate test method to ensure that the formaldehyde has been satisfactorily treated, the solution may be suitable for disposal to the sanitary sewer where it meets applicable local and/or state discharge requirements.

Along with the technology, SCIGEN supplies a screening test kit for field-testing treated solutions for residual formaldehyde; however, SCIGEN's screening test kit is not considered part of the technology undergoing a certification evaluation, and is not a certified or a standard test method.

Certification Statement

The SCIGEN NEUTRALEX technology is hereby certified by the Department of Toxic Substances Control, pursuant to California Health and Safety Code Section 25200.1.5, as a hazardous waste treatment technology when used, monitored, and maintained according to the manufacturer's standards and specifications and the conditions imposed by this Certification. The certified technology has been determined to be effective for treatment of waste from use of 10% neutral buffered Formalin (an aqueous solution containing approximately 3.7% formaldehyde by weight, with added buffers to maintain a neutral pH and about 0.5-1.5% methanol as a preservative) for histopathology tissue specimen preservation and automated tissue processors in the health care industry. The technology is a batch process that treats wastes in increments of liters or gallons. The technology has been shown to be capable of achieving reductions in formaldehyde concentration in the wastes to less than 10 ppm residual formaldehyde when used in accordance with SCIGEN's standard operating procedures. The effectiveness of the treatment for each treated batch must be verified using an appropriate test method. The appropriateness of the SCIGEN screening test kit or other non-standard test method must be verified for each wastestream by comparison to a standard test method.

By treating the formaldehyde in the waste 10% neutral buffered Formalin solution, use of the SCIGEN NEUTRALEX technology as directed has the potential to reduce the exposure to formaldehyde vapors and allow safer management and disposal of the treated wastes. The technology does not generate insoluble polymeric reaction products. Conditions imposed on the user as part of this certification include requirements for worker safety and training, operation of the technology, testing of treated wastes, validation of the test method used, and documentation and recordkeeping. Conditions imposed on the manufacturer include requirements for maintaining quality and providing assistance to the user. The conditions of this certification are specified in detail below.

Specific Conditions

This certification is conditioned upon conformance with the following specific conditions imposed on the user and the manufacturer of the technology:

A. Conditions Imposed on the User of the Technology.

Users of the SCIGEN NEUTRALEX technology shall conform to the following conditions:

1. Safety. The user shall carefully read the Material Safety Data Sheets (MSDSs) for the NEUTRALEX reagents and the screening test kit, and understand safe work practices and precautions. Persons using these materials shall use adequate eye, face, and hand protection and know the location of the nearest eyewash. Treatment shall be performed in a hood or other area with adequate ventilation, and with -secondary containment. The health care facility shall document how it determines that adequate ventilation is provided.

2. Training. All users shall be trained in the proper use of the technology. Training shall be documented.

3. Compliance with discharge requirements. The user shall maintain adequate records to demonstrate that it is in compliance with all applicable pretreatment standards and with all applicable industrial waste discharge requirements issued by the agency operating the publicly owned treatment works (POTW) into which the wastes are discharged.

4. Standard operating procedures. The user shall follow the standard operating procedures provided by SCIGEN.

5. Testing. The user shall test each batch of treated waste for residual formaldehyde concentration and pH. Residual formaldehyde shall be measured using a screening test kit or by a U.S. EPA approved standard method for determination of formaldehyde (e.g., U.S. EPA SW-846 Method 8315).

6. Validation of test method. If the user uses a screening test kit or other non-standard method for the post-treatment testing of residual formaldehyde in the wastes, the user shall establish and implement a program to validate the applicability of the test method. The user shall validate the non-standard test method for each waste stream treated by comparison to a U.S. EPA approved standard method for formaldehyde. At a minimum, the program shall include analysis of a sufficient number of split samples by the U.S. EPA approved analytical method to represent the variability of the waste streams and test methods. The user shall maintain records of all treatment logs, split sample results from the reference method (including identifying what samples were analyzed), and a description of the verification program under which the data were collected for the duration of the certification Upon request by DTSC or other applicable state or local regulatory agencies, the user shall provide copies of records required by this certification.

7. Identification of problems and corrective action. The user shall notify SCIGEN and DTSC of any problems encountered with use of the NEUTRALEX technology, and work with SCIGEN, as appropriate, to resolve them. The user shall maintain a record of any problems encountered from use of the technology and the corrective actions taken.

8. Compliance with conditions under Conditional Exemption. A user operating the NEUTRALEX technology under conditional exemption as specified in Title 22, California Code of Regulations, Section 67450.20, and Health and Safety Code, Section 25201.5, shall comply with all the conditions of Section 25201.5 of the Health and Safety Code.

9. Recordkeeping. The user shall maintain a record of all treatments using NEUTRALEX, including the date, quantity treated, pH, residual formaldehyde concentration, and identification of the person conducting the treatment. All records specified under these conditions shall be maintained on-site for a period of not less than three years.

B. Conditions Imposed on SCIGEN, the Manufacturer of the Technology.

SCIGEN shall conform to the following conditions:

1. SCIGEN shall maintain the quality of the technology at a level equal to or better than that used as the basis for certification.

2. SCIGEN shall assist users, as appropriate, to incorporate SCIGEN's standard operating procedures into the user facility's management System.

3. SCIGEN shall maintain their own management system at a level equal to or better than that in use during the evaluation. This includes, but is not limited to, maintaining their self-assessment, contingency plan, corrective action, and training system.

4. SCIGEN shall assist users to train operators of the technology to perform the treatment operations in accordance with the standard operating procedures.

5. SCIGEN shall provide users with copies of the standard operating procedures for their technology.

6. SCIGEN shall provide users with copies of material safety data sheets conforming to the requirements of 29 Code of Federal Regulations 1910.1200 29 CFR 1910.1200).

7. SCIGEN shall assist users, as appropriate, to resolve any problems that the users encounter with use of the technology.

Certification Limitations/Disclaimer

This Certification is specific to the treatment aspects of the technology. The Certification does not supersede the authority of applicable regulatory agencies to regulate the technology for a particular use or at a particular facility. Where appropriate, the U.S. Environmental Protection Agency, the State Water Resources Control Board, the Regional Water Quality Control Boards, local water districts, and/or other federal, state, and local agencies should be contacted for information on regulatory requirements related to the use of NEUTRALEX at a particular facility.

This Certification is not intended to infringe upon or otherwise affect the activities of the Joint Commission on Accreditation of Healthcare Organizations (JCAHO), the College of American Pathologists (CAP), or other independent health care facility or laboratory accreditation bodies. Where applicable, such organizations should be contacted for more information on their requirements.

The Department makes no express or implied warranties as to the performance of SCIGEN products or equipment. Nor does the Department warrant that the SCIGEN NEUTRALEX products are free from any defects in workmanship or material caused by negligence, misuse, accident, or other causes. Other than as described in this document, the Department has not conducted independent testing to confirm the information submitted by SCIGEN, published in the literature, or gathered from other sources. DTSC has not reviewed SCIGEN's MSDS for conformance to 29 CFR 1910.1200.

The Department does believe, however, that the manufacturer's product or equipment can achieve the performance levels set out in this Certification when used in accordance with the manufacturer's specifications. Said belief is based on a review of 1) data and information submitted by SCIGEN, 2) a field demonstration conducted at two health care facility laboratories, and 3) information gathered from independent sources.

This Certification is issued as part of a pilot project for the California Environmental Technology Certification Program, which has been established under the authority of the Health and Safety Code, Division 20, Section 25200.1.5. The pilot project's purpose is to delineate the practical aspects of the program that will be adopted in regulations. This Certification may be subject to additional conditions that will be required in these regulations, including, but not limited to, the duration of the Certification, continuing monitoring and oversight requirements, and Certification amendment procedures, including those for decertification.

This Certification is specifically limited to the treatment of liquid 10% NBF waste from pathology laboratory tissue preservation and from automated tissue processors. The scope of this Certification does not include treatment of other waste streams, or treatment of formaldehyde formulations containing ingredients other than aqueous formaldehyde, inert buffering agents and methanol stabilizer. The MSDS should be reviewed for specific information on incompatibilities.

Basis for Certification

The certification evaluation included a consideration of the scientific principles behind the technology; a review of studies conducted by SCIGEN; participation in field demonstrations at two health care facilities; and discussions with end users. Detailed results of the certification evaluation are presented in the DTSC Certification Evaluation Report for this technology.

Scientific Principles

NEUTRALEX is a proprietary mixture of specific ingredients combined in proportions optimized to achieve the observed results. The reaction chemistry, and thus the adequacy of the treatment, depends on the exact chemicals present in the reaction mixture and the amounts of each chemical used.

The underlying scientific principles are based on the patented reaction of a particular sulfuric reducing agent with aqueous formaldehyde at near-neutral pHs. SCIGEN asserts a proprietary interest over their formulation which containing this reducing agent plus other key ingredients. The scientific basis for the reactions are described in more detail in the DTSC technology certification evaluation report.

There is substantial literature precedent for reactions of this particular sulfuric reducing agent with formaldehyde or related aldehydes. The reaction of the reducing agent with aqueous Formalin to produce sodium hydroxymethanesulfonate has been patented. It has been studied as a reagent in a method for air sampling for formaldehyde. Its addition to urea resins used in the manufacturer of resin-bonded particle board has been studied as a way to reduce formaldehyde emissions from the board. The reducing agent has also been identified in a patent as a way to prepare a sulfonated melamine-formaldehyde resin with very low free formaldehyde content. Its reaction with dilute aqueous glutaraldehyde has been patented as a way to prevent turbidity and precipitation. It has also been studied as a reagent for the titrimetric analysis of glutaraldehyde.

SCIGEN provided DTSC with a mechanistic pathway and experimental data on major reaction products expected from the mechanism. The mechanism predicts specific products, and a ratio in which they could be formed. To support the mechanism SCIGEN submitted data including a melting point and a C,H,N, and S analysis supporting the formation of a major product expected by the mechanism. They reported the results from an experiment in which they isolated approximately 75% of the amount of this compound predicted by the mechanism. This result, where they did not attempt to optimize their isolation method, provides good support for the proposed mechanism.

Existing Data and Information

DTSC staff visited SCIGEN's facility to discuss SCIGEN's management and operations and to review related documents. SCIGEN maintains documented procedures for handling, storage, packaging, preservation, and delivery of the product, and other customer services. SCIGEN also documents procedures to review their operations and perform internal audits, calibrations, and testing, and to collect, track, and resolve user complaints or product failures. A toll-free telephone number is available for customers to request information or assistance, or present complaints.

During the site visit, DTSC staff confirmed that experiments from product research, development, and testing were retained in notebooks and available for review. The notebooks predated SCIGEN's entry into the certification program. The notebooks showed the progression of the development of the technology. SCIGEN's internal studies and experiments used SCIGEN's modification of ASTM Method D-2194 and the SCIGEN screening test kit to determine formaldehyde concentrations.

SCIGEN submitted a summary of an internal experiment to demonstrate the repeatability of the treatment process. They treated ten batches of unused 10% NBF according to their standard operating procedures. The batches were treated over a period of twelve weeks. Post-treatment pHs were between 6.4 and 6.5. The post-treatment formaldehyde concentrations were between 49 and 58 ppm according to their modification of ASTM Method D-2194, and between 10 and 20 ppm by SCIGEN's Screening Test Kit. The data are consistent with SCIGEN's statements that the reaction repeatably gives low residual formaldehyde concentrations. No quality assurance/quality control (QA/QC) data were submitted for the experiment. In the absence of QA/QC data, the data are best considered as qualitative or semiquantitative. They were used to help identify objectives for field demonstrations, and reviewed for consistency with the results of the field demonstrations and information from end users.

SCIGEN also submitted laboratory data from aquatic bioassay 96-hour LC50 tests performed on two untreated and two treated wastes collected from each of two health care facility wastes. An independent California Department of Health Services Certified Laboratory performed the bioassays. The results showed no fish mortality in post-treatment wastes, indicating an aquatic LC50  >750 mg/kg. The pH during the bioassay was approximately 6.5-7.0, compared to a pH of 7.5 for a control tank.

Field Demonstrations

As part of the evaluation, DTSC participated in a short-term demonstration of the technology at two pathology laboratories, Kaiser-Berkeley and Kaiser-Bellflower. The purposes of the demonstration were to:

  • Observe the use of the technology under field conditions,
  • Obtain confirmatory data from an unbiased laboratory independent from SCIGEN, DTSC's Hazardous Materials Laboratory (HML),
  • Generate data using three analytical methods to provide complementary data related to SCIGEN's claims, and to support the utility of existing data previously generated by SCIGEN and end users. The three methods are:

EPA Method 8315, using derivatization followed by analysis by High Performance Liquid Chromatography-performed by HML;

ASTM Method D-2194, using derivatization followed by titrimetric analysis to measure base released during the derivatization-performed by SCIGEN;

SCIGEN's field screening test kit for residual formaldehyde-performed by HML, SCIGEN, and the Kaiser laboratory.

A summary of these methods is included in the DTSC Certification Evaluation Report for this technology. SCIGEN provided the two Kaiser pathology laboratories with the NEUTRALEX technology, and demonstrated the technology's use. Kaiser pathology laboratory staff performed the treatment, while DTSC staff observed the operations. The two Kaiser pathology laboratories are regional facilities that prepare pathology specimens for a number of hospitals.

The Kaiser-Berkeley facility typically generates about five gallons of tissue processor waste and about two to three gallons of histopathology waste per day. At the Kaiser-Berkeley facility, a staff technician treated the two wastestreams, and poured the samples into the pre-labeled sample jars. The same technician conducted the operations each week. After 15 minutes, the technician tested the pH, then used SCIGEN's screening test kit to test for residual formaldehyde. At the Kaiser-Bellflower facility, the demonstration was carried out in a manner similar to that at Kaiser Berkeley, however insufficient tissue processor waste was available for treatment. DTSC personnel were present during the demonstration activities.

Samples of the wastes before and after treatment were shipped to HML and to SCIGEN from the Kaiser facilities. HML treated an aliquot of the untreated wastes with the NEUTRALEX according to the directions accompanying the technology, with the following modification: since less than one gallon was treated, the package of NEUTRALEX was weighed, and a proportionate amount to achieve the same ratio as one package per gallon of waste was used. Samples analyzed at HML included samples generated at Kaiser-Berkeley during both field study treatment days, and at Kaiser-Bellflower during the second study treatment day. Analyses were performed in accordance with HML's quality assurance and quality control procedures. The EPA Method 8315 analyses were run as routine analyses. The analysts were advised of the presence of buffering agents that could influence the derivatization of formaldehyde during this analytical method. Treatment of samples with NEUTRALEX and SCIGEN screening test kit analyses were run as a special project, since the procedures used did not follow standard methods. The screening tests and pH measurements were run according to the directions and equipment supplied with the technology. HML staff noted that during treatment the temperature of the solution rose from room temperature (not recorded) to 33 degrees Celsius.

SCIGEN analyzed the samples that they received using their modification of ASTM Method D-2194. This method relies on the reaction of formaldehyde with excess sodium bisulfite, followed by titration of the hydroxide ion released as part of the reaction. SCIGEN analyzed each sample using this method. In addition, each treated sample was analyzed for pH using a pH meter and for formaldehyde using the SCIGEN screening test kit. SCIGEN did not submit any QA/QC data associated with their analyses.

Data from the three test methods gave consistent results. Blanks, with and without NEUTRALEX, showed no detectable formaldehyde. The detection limit for EPA Method 8315 was 0. I mg/L for treated samples and blanks. Samples known to contain 10% NBF (approximately 37,000 ppm formaldehyde) gave readings of between 34,000 and 41,000 by EPA Method 83 I 5, and between 34,400 and 43,200 by SCIGEN's modification of ASTM Method D-2194. Samples that had been treated gave readings of between <O. I mg/L and 2 mg/L by EPA Method 8315, and between 28 and 76 mg/L by SCIGEN's modification of ASTM Method D-2194. According to SCIGEN, ASTM Method 2194 (and their modification) is biased high for determination of formaldehyde in IO% NBF due to the presence of the buffers that interfere with the titration (i.e., it requires more acid to titrate the solution back to its initial pH). Because of the limited data, statistical tests were not performed. The results are also consistent with the results from SCIGEN's internal studies on other wastes.

The results from EPA SW-846 Method 8315, a standard analytical method, were considered the most reliable and accurate of the three methods used to provide data for the evaluation. The results from use of this method during the field demonstrations consistently gave results showing less that 10 ppm formaldehyde in treated wastes. However, since the data are limited, a condition of the certification is that each end user validate the effectiveness of the technology on their wastes.

Discussions With End Users

The NEUTRALEX technology was discussed with representatives from eight health care facilities. Six of the eight facilities use the technology and are satisfied with the product. The other two do not currently use the technology for administrative reasons unrelated to its performance. One of the two stated that they had conducted limited tests of the technology, and that it appeared to work well. They stated that they may decide to use the technology in the future. The six users did not identify any problems with use of the NEUTRALEX. Four of the six treat between one and five gallons per week, while the other two treat 10-15 gallons/week. Four of the users treat both wastestreams, while the others treat only histopathology tissue specimen preservation wastes. Four of the six stated that they prefer the technology to competing technologies that generate a precipitate. Five of the six users stated that SCIGEN visited their facility to train them on use of the technology. The other user stated that they observed a demonstration at a trade show. All users said that they felt the technology was easy to use, and works well. Only three of the six users test the wastes following treatment. SCIGEN submitted copies of log sheets from Hoag Memorial Hospital recording four months of treatment with NEUTRALEX. During the four-month period, Hoag Memorial Hospital treated a total of 116 gallons. Treatment was usually carried out in two-gallon batches, every 1-3 working days. The log shows a range of recorded residual formaldehyde concentrations of 0-10 ppm measured using SCIGEN's screening test kit. The post-treatment pHs ranged from 5.5 to 7.75. The other two users who test their wastes indicated that the test kit showed similar low levels of residual formaldehyde in their treated wastes.

Regulatory Considerations

Title 22, California Code of Regulations, Section 67450-20, specifies that treatment of formaldehyde by health care facilities using any technology certified as effective for that purpose is authorized for operation under a grant of conditional exemption. The treatment must be operated pursuant to the conditions imposed on the certification. In addition, the generator conducting the treatment must comply with the conditions of Section 25201.5 of the Health and Safety Code. The reader should refer to these statutory and regulatory sections for additional information.

Duration of the Certification

This certification will remain in effect for the period of three years from the date of issuance, unless it is revoked for cause or unless a duration for certification different from that . specified in this certification is adopted in regulations. If a different duration is specified in regulations, the duration of this certification will be that provided for in the regulations, beginning from the date of issuance of this certification.

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