Excavation and trenching - California

California operates an OSHA-approved State Plan covering most private sector workers and all state and local government workers.

Cal/OSHA’s excavation regulations apply to all open excavations made on the earth's surface. “Excavation” is defined as any man-made cut, cavity, trench, or depression in an earth surface, formed by earth removal.

California’s excavation requirements generally follow the federal OSHA regulations with the additions and differences in the areas of subsurface installations (utilities), hazardous atmospheres, fall protection, trench shield systems, and permitting.

Subsurface installations

Commencement of excavation. An excavation must not begin until:

• The excavation area has been marked as specified in Government Code Section 4216.2 by the excavator;
• The excavator has received a positive response from all known owner/operators of subsurface installations within the boundaries of the proposed project;
• The responses confirm that the owner/operators have located their installations; and
• The responses either advise the excavator of those locations or advise the excavator that the owner/operator does not operate a subsurface installation that would be affected by the proposed excavation.

High-priority subsurface installations. When the proposed excavation is within 10 feet of a high priority subsurface installation:

• The excavator must be notified by the facility owner/operator of the existence of the high priority subsurface installation before the legal excavation start date and time in accordance with Government Code Section 4216.2(a); and
• An onsite meeting involving the excavator and the subsurface installation owner/operator's representative must be scheduled at a mutually agreed time to determine the action or activities required to verify the location of such installations.

“High-priority subsurface installations” are high pressure natural gas pipelines with normal operating pressures greater than 415 kPA gauge (60 p.s.i.g.), petroleum pipelines, pressurized sewage pipelines, conductors or cables that have a potential to ground of 60,000 volts or more, or hazardous materials pipelines that are potentially hazardous to employees, or the public, if damaged.

Locating qualifications. Only qualified persons may perform subsurface installation locating activities, and all such activities must be performed in accordance with applicable state regulations. The required training for locating activities is described in the state regulations.

Notification and excavation training. Employees who are involved in the excavation operation and exposed to excavation operation hazards must be trained in the excavator notification and excavation practices required by state regulations.

Minimum two-day notice. All Regional Notification Centers as defined by Government Code Section 4216(j) in the area involved and all known owners of subsurface facilities in the area who are not members of a Notification Center must be advised of the proposed work at least two working days prior to the start of any digging or excavation work, unless the work is emergency repair work to subsurface facilities as defined in Government Code Section 4216(s).

Damage prevention. When excavation or boring operations approach the approximate location of subsurface installations, the exact location of the installations must be determined by safe and acceptable means that will prevent damage to the subsurface installation.

Open excavation safeguards. While the excavation is open, subsurface installations must be protected, supported, or removed as necessary to safeguard employees.

Notification of damage. An excavator discovering or causing damages to a subsurface installation must immediately notify the facility owner/operator or contact the Regional Notification Center to obtain subsurface installation operator contact information immediately after which the excavator must notify the facility operator. All breaks, leaks, nicks, dents, gouges, grooves, or other damage to an installation's lines, conduits, coatings or cathodic protection must also be reported to the subsurface installation operator.

High priority subsurface installation damage. If damage to a high-priority subsurface installation results in the escape of any flammable, toxic, or corrosive gas or liquid or endangers life, health or property, the excavator must immediately notify 911, or the appropriate emergency response personnel having jurisdiction, and the facility owner/operator.

Details of damage reported to regional notification center. Immediately after calling 911 emergency services or other emergency responders as necessary, and no longer than 2 hours after the excavator's knowledge of the damage, the excavator must notify the appropriate regional notification through the center's website or mobile application, as available, or by phone center of:

• Damage to natural gas or hazardous liquid pipeline subsurface installation regardless of whether the damage results in the escape of any flammable, toxic, or corrosive gas or liquid;
• Damage to high priority subsurface installation of any kind;
• Damage causing injury that requires treatment at a facility that provides medical services; or
• Damage causing fatality.

The notification must also include the following, as may be known to the excavator:

• Excavator's contact information;
• Location of the damage;
• Type of subsurface installation;
• Approximate date and time the damage occurred;
• Whether damage caused fire or evacuation; and
• Type of excavation equipment or tool used by the excavator when the damage occurred or when the excavator discovered the damage.

Hazardous atmospheres

Whenever internal combustion engine-driven equipment is operated inside a shaft, a ventilation system must be provided and operated in accordance with applicable regulations.

Fall protection

Adequate barrier physical protection must be provided at all remotely located excavations. All wells, pits, shafts, etc., must be barricaded or covered. Upon completion of exploration and other similar operations, temporary wells, pits, shafts, etc., must be backfilled.

Trench shield systems

In addition to the trench shield system requirements contained in the federal regulations contained in 29 CFR 1926.652(g)(1) and (2), California regulations require that the sides of the shield extend a minimum of 18 inches above the vertical walls of compound excavations. And on vertically cut trenches, the shield must extend to at least the catch point of the trench.

California permitting requirement

California regulations require an annual or project permit for construction of trenches or excavations five feet or deeper into which any person is required to descend. For purposes of this requirement, the term “descend” means to enter any part of the trench or excavation once the excavation has attained a depth of five feet or more.

The permit requirement does not apply to:

• Government bodies, such as the United States of America, its officers or agencies; and the State of California, county, city and county, city, or district;
• Any public utility subject to the jurisdiction of the California Public Utilities Commission;
• Construction of trenches or excavations for the purpose of performing emergency repair work to underground facilities;
• Construction or final use of excavations or trenches where the construction or final use does not require a person to descend into the excavation or trench;
• Excavation for the construction of graves; or
• Excavation for the construction of swimming pools.