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 an initial hazardous materials list to be provided by Tenant prior to the Term Commencement Date and which shall be subject to Landlord’s approval, not to be unreasonably withheld, conditioned or delayed (“Tenant’s Hazardous Materials”), provided that the same shall at all times be:

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 initially listed on Exhibit 8 attached hereto and otherwise used by Tenant in the ordinary course of business in compliance with Environmental Laws and the requirements of this Lease (“Tenant’s Hazardous Materials”), provided that the same shall at all times be:

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.

Prohibition. Except for de minimis quantities of standard office supplies and cleaning materials stored in compliance with Environmental Laws (hereinafter defined) and in proper containers, Tenant shall not, without the prior written consent of Landlord, which may be withheld in Landlord’s sole discretion, bring or permit to be brought or kept in or on the Premises or elsewhere in the Building # any inflammable, combustible or explosive fluid, material, chemical or substance; or # any Hazardous Material (hereinafter defined). Upon at least forty-eight (48) hours’ notice, except that no notice shall be required in an emergency, Landlord shall have the right, from time to time, to inspect the Premises for compliance with the terms of this Section 15.1 at Tenant’s sole cost and expense.

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.

Except in compliance with applicable Legal Requirements, Tenant shall not bring or keep, or permit to be brought or kept, in the Premises or the Building any "hazardous substance" (as hereinafter defined) without Landlord's prior written consent (which shall not be unreasonably withheld, conditioned or delayed). Except in compliance with applicable Legal Requirements, Tenant shall not use, produce, process, manufacture, generate, treat, handle, store or dispose of any hazardous substance in the Premises or the Building, or use the Premises for any such purpose, or emit, release or discharge any hazardous substance into any air, soil, surface water or groundwater comprising the Premises or the Building, or permit any person using or occupying the Premises to do any of the foregoing without Landlord's prior written consent (which shall not be unreasonably withheld, conditioned or delayed). The preceding sentence shall not prohibit the ordinary use of any hazardous substance normally used in the operation of Tenant's business as permitted by this Lease, provided the amount of any such hazardous substance does not exceed the quantity necessary for the normal operation of Tenant’s business and the use, storage and disposal of any such hazardous substance strictly comply with all applicable "environmental laws" (as hereinafter defined). Tenant shall comply, and shall cause all persons using or occupying the Premises to comply, with all environmental laws applicable to the use or occupancy of the Premises by Tenant or any operation or activity of Tenant therein.

The Tenant shall not keep in the Premises or in the Building any dangerous or explosive or corrosive materials or fluids or batteries or other goods containing dangerous, explosive or corrosive materials or fluids. The Tenant shall not use or keep in the Premises or the Building any flammable or combustible fluid or material other than limited quantities thereof reasonably necessary for the operation or maintenance of office equipment. The Tenant shall not, without the Landlord's prior written approval, use any method of heating or air-conditioning other than that supplied or approved by the Landlord.

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'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 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.