Delaware is under federal OSHA jurisdiction which covers most private sector workers within the state. State and local government workers are not covered by federal OSHA.
Underground utilities
The Delaware Underground Utility Damage Prevention and Safety Act requires excavators to notify operators of underground utilities of their intent to excavate so that operators can mark underground utilities and thereby avoid damage to the utilities and injury to excavation workers. These rules are found in 26 Del. C. §§ 801 – 813.
Particulate emissions from construction (including excavation)
No person may cause or allow land clearing, land grading (including grading for roads), excavation, or the use of non-paved roads on private property unless methods are employed to control dust emissions, when the Department of Natural Resources and Environmental Control determines that such activities could emit dust in quantities sufficient to cause air pollution.
Delaware: 26 Del. C. §§ 801 – 813; CDR 7-1000-1106, section 3.0
Federal: 29 CFR 1926.650; 1926.651; 1926.652