A toeboard is a lowest-lying blockade between 4 and 12 inches in height, as part of the guardrail system closest to the walking-working surface, that prevents building materials, implements, and tools from falling to a lower level. Usually, toeboards also protect workers (mostly roofers) by restricting them from getting hurt when they fall off the platform, gangway, ladder, or scaffold.
OSHA Standard Numbers 1910.28(b)(3)(iv), 1910.28(b)(3)(v)(B), and 1910.28(c)(1) mention toeboard requirements as mandatory. OSHA Standard Number 1910.29(k) stipulates its essential function as a deterrent from falling objects:
Height Requirement: “have a vertical minimum height of 3.5 inches (9 cm) as measured from the top edge of the toeboard to the level of the walking-working surface”,
Clearance: “do not have more than a 0.25 inch (0.5 cm) clearance or opening above the walking-working surface”, and
Force: “should be capable of withstanding a force of at least 50 pounds (222 N) applied in any downward or outward direction at any point along the toeboard.”