Tenant shall not (either with or without negligence) cause or permit the escape, the disposal or release of any Hazardous Materials on or under the Building, the Lot or the Demised Premises. Tenant shall not allow the storage or use of Hazardous Materials in any manner not sanctioned by the applicable permits or by law. Tenant shall not cause any Hazardous Materials to be brought into the Building, Lot or Demised Premises except such substances or materials used in the ordinary course of Tenant’s business and listed on [Exhibit F] attached hereto (which Hazardous Materials shall be used, stored and disposed of in accordance with a program to be mutually agreed upon by Landlord and Tenant) or as otherwise approved by Landlord in writing, which approval shall not be unreasonably withheld, provided such use complies with the permitted allocated quantities of specified classes of chemicals permitted in the Building. Any Hazardous Materials used by Tenant shall at all times be brought to, kept at or used in so-called ‘control areas’ (the number and size of which shall be identified in the plans for Tenant’s Work which are subject to Landlord’s approval pursuant to this Lease) and in accordance with all applicable laws and ordinances, any permit or approval issued by any applicable governmental agency or authority and prudent environmental practice and (with respect to medical waste and so-called “biohazard” materials) good scientific and medical practice. In the event Tenant intends on using any biologically or chemically active or other Hazardous Materials, or materials that require a specialized permit, Tenant shall first obtain Landlord’s prior consent, which shall not be unreasonably withheld, conditioned or delayed. Within five (5) business days of Landlord’s request, Tenant shall provide Landlord with a list of all biologically or chemically active or other Hazardous Materials, including quantities, used by Tenant in the Demised Premises or otherwise in the Building. Tenant shall obtain and maintain all proper permits required by applicable law or ordinance for the storage and use of any Hazardous Materials stored or used by Tenant, and Tenant shall furnish evidence of same upon request and shall comply with all governmental reporting requirements with respect to such Hazardous Materials used by Tenant in its business operations, and shall deliver to Landlord copies of such reports. “Hazardous Material” means # any hazardous, flammable, explosive or toxic materials, radioactive materials, asbestos in any form that is or could become friable, or polychlorinated biphenyls (PCBs); or # any chemical, material or substance defined, classified or regulated as toxic or hazardous or as a pollutant, contaminant or waste under any applicable environmental laws, including without limitation, those hazardous substances and materials described in the Comprehensive Environmental Response, Compensation and Liability Act of 1980, as amended, 42 U.S.C. Section 9601 et seq., the Resource Conservation and Recovery Act, as amended, 42 U.S.C. Section 6901 et seq., any applicable state or local laws and the regulations adopted under these acts. If any lender or governmental agency shall ever require testing to ascertain whether or not there has been any release of Hazardous Materials on or under the Demised Premises, then the reasonable costs thereof shall be paid by Landlord, unless such release was caused solely by Tenant or persons acting under Tenant, whereupon the reasonable costs of such testing shall be

Section # Tenant’s Hazardous Materials. Tenant shall not, without the prior written consent of Landlord, bring or permit to be brought to or kept at, in or on the Premises or elsewhere in the Building or the Property any Hazardous Materials, excepting only the types and quantities of Hazardous Materials which are used by Tenant in the ordinary course of Tenant’s business and are listed on the schedule attached to this Lease as Exhibit E (“Tenant’s Hazardous Materials”). All such Hazardous Materials shall be stored and used in appropriate ‘control areas’, in accordance with all applicable Environmental Laws and prudent practices (including best practices to minimize quantities of stored Hazardous Materials using a “just in time” method of purchasing the same), and with respect to medical waste and so-called “biohazard” materials, good scientific and medical practice. In no event shall Tenant generate, produce, bring upon, use, store or treat any infectious biological micro-organisms or any other Hazardous Materials with a risk category above the level of Biosafety Level 2 as established and described by the Department of Health and Human Services Publication Biosafety in Microbiological and Biomedical Laboratories (Fifth Edition) (as it may be further revised, the “BMBL”) or such other nationally recognized standards as may be adopted by Landlord from time-to-time. To the extent any Environmental Law establishes maximum quantities of any Hazardous Materials which may be stored, used or brought into the Building without additional licensing, permitting or authorizations therefor, Tenant shall not use, store or bring into the Building quantities in excess of Tenant’s Proportionate Share of such Hazardous Materials. Tenant shall assure that all laboratory uses are adequately and properly vented. By not later than the Commencement Date, Tenant shall complete and deliver to Landlord an Environmental Questionnaire (the “Environmental Questionnaire”) in the form attached to this Lease as Exhibit H, for review and approval by Landlord, which approval shall not be unreasonably withheld, conditioned or delayed. On or before each anniversary of the Commencement Date, Tenant shall submit to Landlord for review and approval by Landlord, which approval shall not be unreasonably withheld, conditioned or delayed, the following: # an updated Environmental Questionnaire, and # an updated schedule listing Tenant’s Hazardous Materials. With respect to any Hazardous Material transported, used, stored, or generated in the Premises, Tenant shall # not permit any such Hazardous Material to escape, be released or be disposed of outside of the Premises, including in the Common Areas or elsewhere in the Building or the Real Property, and # upon request, provide evidence reasonably satisfactory to Landlord of Tenant’s compliance with all applicable Environmental Laws, including copies of all licenses, permits and registrations obtained by Tenant that have not been previously provided to Landlord. Notwithstanding the foregoing, with respect to any of Tenant’s Hazardous Materials which Tenant does not properly handle, store or dispose of in compliance with all applicable Environmental Laws, prudent environmental practice and (with respect to medical waste and so-called “biohazard” materials) good scientific and medical practice, the right of Tenant to use such Hazardous Materials in the Premises shall be suspended unless and until Tenant demonstrates to Landlord’s reasonable satisfaction that Tenant has implemented appropriate and effective protocols and programs to thereafter properly handle, store or dispose of such material. In order to induce Landlord to waive its otherwise applicable requirement that Tenant maintain insurance in favor of Landlord against liability arising from the presence of radioactive materials in the Premises, and without limiting the foregoing, Tenant hereby represents and warrants to Landlord that at no time during the Term will Tenant bring upon, or permit to be brought upon, the Premises any radioactive materials, of any kind, whatsoever.

Tenant shall not cause or permit any Hazardous Materials to be brought upon, stored, used, generated, released or disposed of on, under, from or about the Premises (including without limitation the soil and groundwater thereunder) without the prior written consent of Landlord, which consent may be given or withheld in Landlord’s sole and absolute discretion. Notwithstanding the foregoing, Tenant shall have the right, without obtaining prior written consent of Landlord, to utilize within the Premises (collectively, the “Permitted Hazmats”): # a reasonable quantity of standard office and cleaning products that may contain Hazardous Materials (such as photocopy toner, “White Out”, and the like), provided however, that Tenant shall follow all instructions with respect to the storage, use and disposal of such products; and # those Hazardous Materials in kind and content listed on the Survey Form delivered to Landlord prior to the execution of this Lease. Tenant shall comply with all applicable laws with respect to such products, and # all of the other terms and provisions of this Section 5.3 shall apply with respect to Tenant’s storage, use and disposal of all Permitted Hazmats. Landlord may, in its sole and absolute discretion, place such conditions as Landlord deems appropriate with respect to Tenant’s use, storage and/or disposal of any Hazardous Materials requiring Landlord’s consent. Tenant understands that Landlord may utilize an environmental consultant to assist in determining conditions of approval in connection with the storage, use, release, and/or disposal of Hazardous Materials by Tenant on or about the Premises, and/or to conduct periodic inspections of the storage, generation, use, release and/or disposal of such Hazardous Materials by Tenant on and from the Premises, and Tenant agrees that any costs incurred by Landlord in connection therewith shall be reimbursed by Tenant to Landlord as additional rent hereunder upon demand.

Tenant shall not, without the prior written consent of Landlord, bring or permit to be brought to or kept at, in or on the Premises or elsewhere in the Building or the Property # any inflammable, combustible or explosive fluid, material, chemical or substance (except for de minimis quantities of standard office and cleaning supplies stored in compliance with Environmental Laws (hereinafter defined) and in proper containers); and # any Hazardous Material (hereinafter defined), other than the types and quantities of Hazardous Materials which are used by Tenant in the ordinary course of Tenant’s business and are listed on [Exhibit 13] attached hereto (“Tenant’s Hazardous Materials”), provided that the same shall at all times be brought to, kept at or used in so-called ‘control areas’ (the number and size of which shall be identified in the Approved Plans which are subject to Landlord’s approval pursuant to the Work Letter) and in accordance with all applicable Environmental Laws (hereinafter defined), any permit or approval issued by any applicable governmental agency or authority and prudent environmental practice and (with respect to medical waste and so-called “biohazard” materials) good scientific and medical practice, and provided further that in no event shall Tenant generate, produce, bring upon, use, store or treat any infectious biological micro-organisms or any other Hazardous Materials in the Premises with a risk category above the level of Biosafety Level 2 as established and described by the Department of Health and Human Services Publication Biosafety in Microbiological and Biomedical Laboratories (Fifth Edition) (as it may be further revised, the “BMBL”) or such nationally recognized new or replacement standards as may be reasonably selected by Landlord; and provided further that to the extent any Legal Requirement sets a maximum quantity of any Hazardous Materials which may be stored, used or brought into the Building without additional licensing, permitting or authorizations therefor, Tenant shall not be permitted to use, store or bring into the Building more than such maximum quantity of such Hazardous Materials. In all events, Tenant shall comply with all applicable provisions of the BMBL. Tenant shall be responsible for assuring that all laboratory uses are adequately and properly vented. Without limiting the foregoing, Tenant shall keep and store at the Premises only such quantities of Tenant’s Hazardous Materials that Tenant reasonably believes to be necessary for the conduct of its ordinary course of business and consistent with prudent industry practice. On or before each anniversary of the Rent Commencement Date, and at least thirty (30) days prior to any earlier date during the 12-month period on which Tenant intends to add a new Hazardous Material to, or materially increase the quantity of any Hazardous Material already on, the list of Tenant’s Hazardous Materials, Tenant shall submit to Landlord an updated list of Tenant’s Hazardous Materials for Landlord’s review and approval, which approval shall not be unreasonably withheld, conditioned or delayed. Tenant shall provide such further information concerning any Tenant’s Hazardous Materials and/or their use, storage and/or disposal within thirty (30) days of Landlord’s reasonable request concerning the same. Landlord shall have the right, from time to time, to inspect the Premises for compliance with the terms of this Section 17.1 at Tenant’s sole cost and expense. With respect to any Hazardous Material brought or permitted to be brought or kept in or on the Premises or elsewhere in the Building or the Property in accordance with the foregoing, Tenant shall # not permit any such Hazardous Material to escape, be released or be disposed in or about the Premises, the Building or the Land and # within five (5) business days of Landlord’s reasonable request, which request shall not be made more frequently than one time per calendar year unless otherwise required by a governmental authority or Landlord reasonably suspects, that a release of a Hazardous Material has occurred upon the Premises, provide evidence reasonably satisfactory to Landlord of Tenant’s compliance with all applicable Environmental Laws including copies of all licenses, permits and registrations that Tenant has been required to obtain prior to handling any Hazardous Material at the Premises and that have not been previously provided to Landlord. Notwithstanding the foregoing, with respect to any of Tenant’s Hazardous Materials which Tenant does not properly handle, store or dispose of in compliance with all applicable Environmental Laws (hereinafter defined), prudent environmental practice and (with respect to medical waste and so-called “biohazard” materials) good scientific and medical practice, Tenant shall, upon written notice from Landlord, no longer have the right to bring such material into the Building or the Property until Tenant has demonstrated, to Landlord’s reasonable satisfaction, that Tenant has implemented programs to thereafter properly handle, store or dispose of such material. In order to induce Landlord to waive its otherwise applicable requirement that Tenant maintain insurance in favor of Landlord against liability arising from the presence of radioactive materials in the Premises, and without limiting the foregoing, Tenant hereby represents and warrants to Landlord that at no time during the Term will Tenant bring upon, or permit to be brought upon, the Premises any radioactive materials, other than such radioactive materials allowed by Tenant’s existing permit and such other radioactive materials approved by the Massachusetts Department of Public Health Radiation Control Program of which Landlord has provided its prior written approval, and are used, stored and disposed of in compliance with all Legal Requirements.

Tenant's Obligations – Hazardous Materials. Except as expressly permitted herein, Tenant agrees not to cause or permit any Hazardous Materials to be brought upon, stored, used, handled, generated, released or disposed of on, in, under or about the Premises, or any other portion of the Property by Tenant, its agents, employees, subtenants, assignees, licensees, contractors or invitees (collectively, "Tenant's Parties"), without the prior written consent of Landlord, which consent Landlord may withhold in its sole and absolute discretion (except as provided below). Landlord acknowledges that it is not the intent of this Section 5.2 to prohibit Tenant from operating its business for the uses permitted hereunder. Tenant may operate its business according to the custom of Tenant's industry so long as the use or presence of Hazardous Materials is strictly and properly monitored in accordance with applicable Environmental Laws. As a material inducement to Landlord to allow Tenant to use Hazardous Materials in connection with its business, Tenant agrees to deliver to Landlord prior to the Lease Commencement Date a list identifying each type of Hazardous Material to be present at the Premises and setting forth any and all governmental approvals or permits required in connection with the presence of such Hazardous Material at the Premises (the "Hazardous Materials List"). Tenant shall deliver to Landlord an updated Hazardous Materials List on or prior to each annual anniversary of the Lease Commencement Date and shall also deliver an updated Hazardous Materials List before any new Hazardous Materials are brought to the Premises. Landlord shall not unreasonably withhold, condition or delay its consent to any changes to the Hazardous Materials List provided that the types and quantities of Hazardous Materials stated therein are of the type and amount customarily used by tenants of comparable first-class biotechnology projects, including other tenants of the Project. Tenant shall deliver to Landlord true and correct copies

Tenant shall not cause or permit any Hazardous Material to be brought upon, kept or used in or about the Premises or otherwise in the Complex by Tenant, its agents, employees, contractors or invitees, without the prior written consent of Landlord, except for Hazardous Materials which are typically used in the operation of offices or laboratories, provided that such materials are stored, used and disposed of in strict compliance with all applicable Environmental Laws and with good scientific and medical practice. Within twenty (20) days of Landlord’s request, Tenant shall provide Landlord with a list of all Hazardous Materials, including quantities used and such other information as Landlord may reasonably request, used by Tenant in the Premises or otherwise in the Complex. Tenant represents that the list attached hereto as [Exhibit J] is a complete list of all Hazardous Materials and quantities that may be used by Tenant in the Premises as of the Execution Date, which list Tenant may supplement or revise during the Term. Notwithstanding the foregoing, with respect to any of Tenant's Hazardous Material which Tenant does not properly handle, store or dispose of in compliance with all applicable Environmental Laws and good scientific and medical practice, Tenant shall, upon written notice from Landlord, no longer have the right to bring such material into the Premises, Building of which the Premises is a part until Tenant has demonstrated, to Landlord's reasonable satisfaction, that Tenant has implemented programs to thereafter properly handle, store or dispose of such material.

Tenant shall not cause or permit any Hazardous Materials (as defined below) to be brought upon, kept or used in or about the Premises in violation of Applicable Laws by Tenant or any of its employees, agents, contractors or invitees (collectively with Tenant, each a “Tenant Party”). If # Tenant breaches such obligation, # the presence of Hazardous Materials as a result of such a breach results in contamination of the Premises, any portion thereof, or any adjacent property, # contamination of the Premises otherwise occurs during the Term or any extension or renewal hereof or holding over hereunder or # contamination of the Premises occurs as a result of Hazardous Materials that are placed on or under or are released into the Premises by a Tenant Party, then Tenant shall Indemnify the Landlord Indemnitees from and against any and all Claims of any kind or nature, including # diminution in value of the Premises or any portion thereof, # damages for the loss or restriction on use of rentable or usable space or of any amenity of the Premises, # damages arising from any adverse impact on marketing of space in the Premises or any portion thereof and # sums paid in settlement of Claims that arise before, during or after the Term as a result of such breach or contamination. This Indemnification by Tenant includes costs incurred in connection with any investigation of site conditions or any clean-up, remedial, removal or restoration work required by any Governmental Authority because of Hazardous Materials present in the air, soil or groundwater above, on, under or about the Premises. Without limiting the foregoing, if the presence of any Hazardous Materials in, on, under or about the Premises, any portion thereof or any adjacent property caused or permitted by any Tenant Party results in any contamination of the Premises, any portion thereof or any adjacent property, then Tenant shall promptly take all actions at its sole cost and expense as are necessary to return the Premises, any portion thereof or any adjacent property to its respective condition existing prior to the time of such contamination; provided that Landlord’s written approval of such action shall first be obtained, which approval Landlord shall not unreasonably withhold; and provided, further, that it shall be reasonable for Landlord to withhold its consent if such actions could have a material adverse long-term or short-term effect on the Premises, any portion thereof or any adjacent property. Tenant’s obligations under this Section shall not be affected, reduced or limited by any limitation on the amount or type of damages, compensation or benefits payable by or for Tenant under workers’ compensation acts, disability benefit acts, employee benefit acts or similar legislation.

Notwithstanding anything to the contrary in this Lease, Tenant, at its sole cost, shall comply with, and shall cause the Tenant Parties to comply with, all Laws relating to the storage, use and disposal of Tenant’s Hazardous Materials at the Property; provided, however, that Tenant shall not be responsible for contamination of the Leased Premises and/or the Buildings or the Property (including any parking garage) by Hazardous Materials # existing as of the date the Leased Premises are delivered to Tenant (whether before or after the Lease Commencement Date), # that have migrated from outside the Leased Premises not caused by Tenant or the Tenant Parties, or # used, stored, disposed or otherwise released by Landlord’s or any Landlord Party, excepting only contamination caused or permitted by Tenant or the Tenant Parties. Tenant shall not store, use or dispose of any Hazardous Materials except for those Hazardous Materials listed in a Hazardous Materials management plan (“HMMP”) which Tenant shall deliver to Landlord within thirty (30) days after mutual execution and delivery of this Lease and update at least annually with Landlord and after any new Hazardous Materials are brought to the Leased Premises (“Permitted Materials”) which may be used, stored and disposed of provided # such Permitted Materials are used, stored, transported, and disposed of in strict compliance with applicable laws, # such Permitted Materials shall be limited to the materials listed on and may be used only in the quantities specified in the HMMP, and # Tenant shall provide Landlord with copies of all material safety data sheets and other documentation required under applicable Laws in connection with Tenant’s use of Permitted Materials as and when such documentation is provided to any regulatory authority having jurisdiction. Landlord agrees to reasonably cooperate with Tenant, at no liability and at material cost to Landlord, in obtaining any permits required by applicable Law for the use of the Leased Premises by Tenant for the Permitted Use, such cooperation to exclude executing or joining in the execution of such applications and other documentation, provided that if Tenant is required by Laws to obtain a conditional use permit or other similar land use approval in order to use the Leased Premises for the Permitted Use and in connection therewith the applicable governmental agency requires Landlord, as owner, to sign a consent or similar document, then Landlord will agree to act reasonably, at no liability and at material cost to Landlord, in connection with such requirement. In no event shall Tenant or any of the Tenant Parties conduct any invasive or destructive environmental tests of the Leased Premises or cause or permit to be discharged into the plumbing or sewage system of the Building or onto the land underlying or adjacent to the Building any Hazardous Materials. Tenant shall be solely responsible for and shall defend, indemnify, and hold Landlord and its agents harmless from and against all claims, costs and liabilities, including attorneys’ fees and costs, arising out of or in connection with Tenant’s storage, use and/or disposal of Hazardous Materials. If the presence of Hazardous Materials on the Leased Premises caused or permitted by Tenant or any of the Tenant Parties results in contamination or deterioration of water or soil, then Tenant shall promptly take any and all action necessary to clean up such contamination, but the foregoing shall in no event be deemed to constitute permission by Landlord to allow the presence of such Hazardous Materials. Tenant shall further be solely responsible for, and shall defend, indemnify, and hold Landlord and its agents harmless from and against all claims, costs and liabilities, including attorneys’ fees and costs, arising out of or in connection with any removal, cleanup and restoration work and materials required hereunder to return the Leased Premises and any other property of whatever nature to their condition as required under applicable Law.

Tenant covenants and agrees that it shall not cause or permit any Hazardous Material (as defined below) to be brought upon, kept, or used in or about the Premises or Building by Tenant, its agents, employees, contractors or invitees. The foregoing covenant shall not extend to substances typically found or used in general office applications so long as # such substances and any equipment which generates such substances are maintained only in such quantities as are reasonably necessary for Tenant’s operations in the Premises, # such substances are used strictly in accordance with the manufacturers’ instructions therefor, # such substances are not disposed of in or about the Building in a manner which would constitute a release or discharge thereof, and # all such substances and any equipment which generates such substances are removed from the Building by Tenant upon the expiration or earlier termination of this Lease (collectively, the “Permitted Customary Office Hazardous Materials”). Any use, storage, generation, disposal, release or discharge by Tenant of Hazardous Materials in or about the Building as is permitted pursuant to this Paragraph shall be carried out in compliance with all applicable federal, state and local laws, ordinances, rules and regulations. Moreover, no Hazardous Materials resulting from any operations by Tenant shall be stored or maintained by Tenant in or about the Building for more than ninety (90) days prior to removal by Tenant (other than Permitted Customary Office Hazardous Materials). Tenant shall, annually within thirty (30) days after Tenant’s receipt of Landlord’s written request therefor, provide to Landlord a written list identifying any Hazardous Materials then maintained by Tenant in the Building, the use of each such Hazardous Material and the approximate quantity of each such Hazardous Material so maintained by Tenant, together with written certification by Tenant stating, in substance, that neither Tenant nor any person for whom Tenant is responsible has released or discharged any Hazardous Materials in or about the Building.

Prohibition. Tenant shall not, without the prior written consent of Landlord, bring or permit to be brought or kept in or on the Premises or elsewhere in the Building or the Property # any inflammable, combustible or explosive fluid, material, chemical or substance (except for standard office supplies stored in proper containers); and # any Hazardous Material (hereinafter defined), other than the types and quantities of Hazardous Materials which are listed on Exhibit 8 attached hereto (“Tenant’s Hazardous Materials”), provided that the same shall at all times be brought upon, kept or used in so-called ‘control areas’ (the number and size of which shall be reasonably determined by Landlord), as described in, and in accordance with, Exhibit 11 attached hereto and in accordance with all applicable Environmental Laws (hereinafter defined) and prudent environmental practice and (with respect to medical waste and so-called “biohazard” materials) good scientific and medical practice. Tenant shall be responsible for assuring that all laboratory uses are adequately and properly vented. On or before each anniversary of the Rent Commencement Date, and on any earlier date during the 12-month period on which Tenant intends to add a new Hazardous Material or materially increase the quantity of any Hazardous Material to the list of Tenant’s Hazardous Materials, Tenant shall submit to Landlord an updated list of Tenant’s Hazardous Materials for Landlord’s review and approval, which approval shall not be unreasonably withheld, conditioned or delayed. Landlord shall have the right, from time to time, to inspect the Premises for compliance with the terms of this Section 17.1. Notwithstanding the foregoing, with respect to any of Tenant’s Hazardous Materials which Tenant does not properly handle, store or dispose of in compliance with all applicable Environmental Laws (hereinafter defined), prudent environmental practice and (with respect to medical waste and so-called “biohazard materials”) good scientific and medical practice, Tenant shall, upon written notice from Landlord, no longer have the right to bring such material into the Building or the Property until Tenant has demonstrated, to Landlord’s reasonable satisfaction, that Tenant has implemented programs to thereafter properly handle, store or dispose of such material. In order to induce Landlord to waive its otherwise applicable requirement that Tenant maintain insurance in favor of Landlord against liability arising from the presence of radioactive materials in the Premises, and without limiting the foregoing, Tenant hereby represents and warrants to Landlord that at no time during the Term will Tenant bring upon, or permit to be brought upon, the Premises any radioactive materials whatsoever.