Unless a permit to construct, State permit to operate, or an approval is revoked by the Department or superseded by another permit, it remains in effect as provided in this regulation. Permits to Construct and Approvals. A permit to construct or an approval expires if, as determined by the Department: Substantial construction or modification is not commenced within 18 months after the date of issuance of the permit or approval, unless the Department specifies a longer period in the permit or approval; Construction or modification is substantially discontinued for a period of 18 months after the construction or modification has commenced; or The source for which the permit or approval was issued is not completed within a reasonable period after the date of issuance of the permit or approval. State Permits to Operate. Except as provided by State Government Article, §10-226(b), Annotated Code of Maryland, a State permit to operate expires 5 years from the date of issuance by the Department, unless an earlier expiration date is specified in the permit. A State permit to operate for a source may be superseded by the issuance of a Part 70 permit covering that source. Temporary Start-Up State Permit to Operate. Notwithstanding §§B and C of this regulation, the Department may issue a temporary start-up State permit to operate for a source or emission unit within the source for a period not to exceed 90 days. In the case of a newly constructed or modified source, the Department may issue a temporary start-up State permit to operate for a period not to exceed 1 year. Portable Emission Units. A permit to construct a portable emission unit at a specific site expires if the Department determines that the portable emission unit has not been located at the site for 3 years. Duration of Part 70 Permits. The duration of Part 70 permits is located in COMAR 26.11.03.05D. Effect of Permit Expiration. Except as otherwise provided in this chapter or COMAR 26.11.03, the expiration of a permit to operate for a source terminates the right of the owner and operator to operate the source.