DISMANTLEMENT OF LABORATORIES PERFORMING

Transcription

1 DISMANTLEMENT OF LABORATORIES PERFORMING RAPID DETECTION OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHY Technical Working Document Expertise, service provision & customer relations Biosafety and Biotechnology Unit Rue Juliette Wystman Brussels Belgium

2 Biosafety and Biotechnology Unit December 2011 Brussels, Belgium Reference: ISP/41/CU/ Dr. Amaya Leunda 1 Dr. Stefan Roels 2 Mrs. Bernadette Van Vaerenbergh 1 1 Biosafety and Biotechnology Unit. Scientific Institute of Public Health ² Orientation and Veterinary Support, NRL for Veterinary TSE. Veterinary and Agrochemical Research Centre Institut Scientifique de Santé Publique Wetenschappelijk Instituut Volksgezondheid, Brussels This report may not be reproduced, published or distributed without the consent of the WIV-ISP. Science at the service of Public health, Food chain safety and Environment. 2

3 Introduction As a consequence of a decreasing number of detected cases of Transmissible Spongiform Encephalopathy (TSE) infection in the recent years, the Belgian Federal Agency for the Safety of the Food Chain (FAFSC) decided to reduce the diagnostic activities of Belgian reference laboratories for TSE. Due to the difficulty to inactivate the TSE agent, the question was raised of what could be the best procedure to dismantle these laboratories. The FAFSC, the Belgian National Reference Laboratory for TSE and the Biotechnology and Biosafety Unit (SBB) of the Scientific Institute of Public Health cooperated to establish a procedure for dismantlement based on the present knowledge on TSE. Everyone agreed to carry out a global risk assessment aiming at minimizing the potential risks (for the public health and the environment) associated with dismantlement of laboratories and treatment of the waste generated during this process. In this technical document, the SBB proposes a dismantlement procedure of laboratories performing rapid diagnosis of TSE and the safety measures to adopt during the process. The prion protein, the causative agent for TSE, is able to remain infectious in the environment for a long time (several years). TSE is a disease developing very slowly and up to now always with a fatal issue. The standard methods for decontamination are not efficient against the prion protein and it is necessary to use a combination of chemical and physical methods to inactivate it. Besides, until now there is no sampling and rapid detection method specific and sensitive enough to detect traces of the prion protein in the environment. Hence it is difficult to know if a laboratory is contaminated or not with the prion protein. A step by step risk assessment carried out before dismantlement could lead to a procedure specific for each concerned laboratory (Leunda-Casi et al, 2009). However, the choice of applying the precautionary principle on the basis of the characteristics of TSE has lead to a unique procedure prescribing complete destruction of all material, equipment and furniture. If necessary, this procedure can be adapted later on taking into account the evolution of scientific knowledge on the subject. This technical working document is based on the original version available in French and Dutch (ref. ISP/41/AL/ ). 3

4 Procedure for decontamination and dismantlement of laboratories performing rapide detection of TSE This procedure concerns only TSE diagnostic laboratories performing rapid detection of TSE on Bovidae, Ovidae and Caprinae. It is to be applied for small and large equipment, furniture and rooms and is partly based on the practical experience of a company specialised in disposal of dangerous waste (SGS EWACS NV). The procedure for dismantlement includes the following steps (in this order): - A cleaning step to eliminate any residual organic matter that can interfere with the disinfectant action; - Decontamination of prions using high concentrations of corrosive and irritating disinfectant solutions such as sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) (HPA, 2011 ; BMBL 5thEd 2009); - Packing of decontaminated equipment and furniture in compliance with the international transport regulations prior to incineration by a waste processing company which disposes of an incinerator for hazardous waste. The head of the laboratory to dismantle assures the traceability of all material leaving the laboratory for incineration. 1. General Dismantlement starts with equipment and furniture in the room and finishes with decontamination of the emptied room. During the entire dismantlement procedure doors and windows are kept closed and air exhaust and ventilation are stopped. Cleaning solutions: 100% protease detergent solution or standard detergent solution devoid of aldehydes or alcohols. Desinfectants: NaOH 2N or NaOCl ppm for 1 hour Technicians performing the dismantlement need to ware personal protection equipment (PPE): Complete body suit, resistant against chemical and biological agents; Full respiratory mask covering the face and resistant against chemical and biological agents, keeping in mind the use of NaOH or NaOCl and the cutting, where necessary, of large equipment (e. g. biosafety cabinet) that may generate infectious dust; Gloves resistant against chemical and biological agents; Boots. The kind of packaging for transport to the incinerator will depend on the volume of the material to be packed: - Sealed biohazard box (120L with plastic lid or 200L with metal lid) ready for transport to the incinerator; - Large pieces are packed in 2 layers of resistant plastic film and disposed in cardboard boxes, ready for transport to the incinerator. In general, biohazard containers should be used preferentially and contamination of the outside walls of the container should be avoided. All packed material leaving the laboratory should be labelled with the universal biohazard symbol. 2. Small equipment Examples: glassware, scale, small centrifuge, pipettes, water bath, heating plate but also small electronic devices such as computer mouse and telephone. Small equipment can be disposed in a biohazard container without prior decontamination. When full, the biohazard box is sealed, labelled with the biohazard symbol and transported to the incinerator. 4

5 3. Large equipment Examples: large centrifuge, plate reader, incubator, large computer devices. The dismantlement and treatment of large equipment will depend on the way it is eliminated at the incineration site. There are two possibilities: either the incinerator entrance is large enough to receive large equipment, either the entrance is too small and large equipment need to be reduced into small pieces before entering the oven (e.g. a rotary kiln oven for incineration of dangerous waste). In case of small incinerator oven entrance, two solutions are proposed: a. Large equipment is cut in the laboratory into pieces small enough to enter the oven. This procedure increases the contamination risk by dispersion of potentially infectious droplets and dust during the cutting. All accessories with adequate dimensions are dismantled and disposed in a biohazard container without prior decontamination. Outside and inside surfaces of large equipment are cleaned with a detergent and then vaporized (humidified) with NaOH 2N or NaOCl ppm for one hour. After rinsing with water (see point 4.7 for proper contaminated water disposal), equipment is cut into pieces with adequate dimensions in a contained cutting area. The containment of this cutting area can be achieved by putting up a containment tent or a protection plastic tarp, or by covering the floor and walls with plastic tarp. The cutting will be performed using an industrial wire cutter or a saw fitted with a dust suction system equipped with with a HEPA filter, in order to suck up dust particles as they are produced. The pieces are packed in 2 layers of resistant plastic film and put in a box with dimensions that do not exceed those of the oven entrance. The box is sealed and labelled with the biohazard symbol, ready for transport to the incinerator. b. Large equipment is crushed just before entering the oven at the incineration site. This procedure avoids the cutting of equipment in the laboratory before its transportation to the incinerator. The risk of dispersion and contamination with the prion protein in the laboratory is thus reduced. For instance, in Belgium, Indaver, a company accredited for incineration of dangerous waste, can provide this service in a closed system. However, the drawback of this procedure is that the grinder will be contaminated and should be properly decontaminated after use. At the laboratory, the outside walls of the equipment will be cleaned with a detergent and then vaporized (humidified) with NaOH 2N or NaOCl ppm for one hour. The equipment will be packed in 2 layers of resistant plastic film, placed in the original or equivalent cardboard packaging, and labelled with the biohazard symbol, ready for transport to the incinerator. 4. Special cases: 4.1. Biological Safety Cabinet The inside and outside surfaces of the Biological Safety Cabinet (BSC) are cleaned with a detergent and then vaporized (humidified) with NaOH 2N or NaOCl ppm during one hour. After rinsing with water (see point 4.7 for proper contaminated water disposal),,hydrogen peroxide fumigation is performed following the Bioquell (wet), the Steris (dry) protocol instructions or any equivalent available decontamination procedure. Filters (HEPA and pre-filters) are fixed with a hairspray in order to avoid dust dispersion at the moment of their dismantlement. They are then removed from the BSC. Depending on the way they will be finally eliminated, filters and BSC will be treated according to one of the proposed dismantlement procedures for large equipment Refrigerators and freezers Refrigerating liquids can be directly eliminated, since they are contained in a separated tank of the refrigerator or freezer and cannot be contaminated. 5

6 Depending on the final way of elimination, these devices will be eliminated according to one of the proposed dismantlement procedures Furniture Examples: lab benches, tables, chairs, storage cabinets, racks. Furniture which can be taken apart is dismantled in the laboratory and eliminated according to one of the proposed dismantlement procedures Documents Documents and other paper material should be destroyed and disposed in a biohazard container for incineration. However, if lab books, note books, reports and any kind of official document must be kept in compliance with the quality system, they will be placed in plastic bags, sealed and stored in a new dedicated and closed cabinet in the laboratory. Time of storage is determined by the quality system in place. If this is not the case, these documents can be scanned for electronic archiving Empty room Walls, floor and any fixed furniture (inside and outside) are cleaned with a detergent and then vaporized (humidified) with NaOH 2N or NaOCl ppm for one hour. All surfaces are rinsed with water and the room is made airtight, fumigated with hydrogen peroxide following the Bioquell (wet), the Steris (dry) or Fogcleaner (atomizer) protocol instructions or any equivalent decontamination equipment and procedure Material used for the dismantlement This material is cleaned, decontaminated and placed in a dedicated closed box. It can be used again for dismantlement of other TSE diagnostic laboratories. Finally, this material will be cleaned, decontaminated and eliminated according to one of the proposed procedures for small or large equipment Waste generated during dismantlement Waste is directly disposed in biohazard boxes. Liquids are poured in a bottle containing NaOH 6N. When full, the bottle will be placed in a biohazard box for incineration. Remarks: Some devices could be re-used by other TSE diagnostic laboratories which remain in activity. This material will be decontaminated and transported as described below. Small equipment which can withstand treatment with NaOH 1N or NaOCl ppm for one hour can be re-used after decontamination, rinsing with water followed by autoclaving (121 C for one hour) (BMBL, 5th Ed, 2009). 6

7 References: Démantèlement des laboratoires effectuant des tests de détection rapide des EST. A Leunda, S Roels, B Van Vaerenbergh., ISP/41/AL/ Ontmanteling van laboratoria die OSE-sneltests verrichten. A Leunda, S Roels, B Van Vaerenbergh., ISP/41/AL/ Biosafety in Microbiological and Biomedical Laboratories, 5th Edition, U.S. Department of Health and Human Services. Public Health Service Centers for Disease Control and Prevention, National Institutes of Health. HHS Publication No. (CDC) , Revised Dec 2009 Transmissible Spongiform Encephalopathy agents: safe working and the prevention of infection. Guidance from the ACDP TSE working group. Annex C. General principles of decontamination and waste disposal (HPA, UK), Risk assessment of laboratories involving the manipulation of unconventional agents causing TSE. A Leunda-Casi, K Pauwels, P Herman, C Verheust, W Zorzi, O Thellin, S Roels, B Van Vaerenbergh. Legal Depot : D/2009/2505/49. 7