OSHA has no single standard for lone workers. Employers must still protect people who work alone from recognised hazards under the General Duty Clause, Section 5(a)(1) of the OSH Act, and must follow any task-specific standard that applies, such as the attendant requirement for permit-required confined spaces in 29 CFR 1910.146. For forklift work, the powered industrial truck standard, 29 CFR 1910.178, applies the same way whether or not the operator is alone. In practice, employers meet the duty with a hazard assessment, a check-in or monitoring method, and a tested plan for reaching an injured worker.
The full guide is Lone worker safety, which covers monitoring options and the response procedure. States that run their own OSHA-approved plans can set requirements beyond federal OSHA, so check the state plan where you operate. For an isolated forklift operator in a yard, a cold store or on a night shift, the hazard assessment should ask how long it would take anyone to notice a tip-over or a fall, and how responders would find the person. Wearables with an SOS button and a man-down alarm shorten that interval; they support the duty but do not replace the assessment. The OSHA forklift regulations guide covers the truck rules. This is general information, not legal advice.