40 CFR §1068.515

1. (a)Attach a label to engines/equipment you repair under the remedial plan. At your discretion, you may label or mark engines/equipment you inspect but do not repair. Designate the specific recall campaign on the label.
2. (b)Make the label from a durable material suitable for its planned location. Make sure no one can remove the label without destroying or defacing it.
3. (c)Identify the facility where you repaired or inspected the engine/equipment on the label, or keep records of this information for each vehicle and give it to us if we ask for it.
4. (d)We may waive or modify the labeling requirements if we determine they are overly burdensome.