What is a blanket additional insured endorsement for oilfield work?

There are two ways to add an operator to your general liability policy.

A scheduled endorsement names the operator. The ISO form CG 20 10 has a schedule with the name of the additional insured and the location of covered operations. Each new operator means a policy change, and if the name on the schedule does not match the legal entity in the MSA, you have a problem.

A blanket endorsement uses a description instead of a name. ISO form CG 20 38 extends additional insured status to "any person or organization for whom you are performing operations when you and such person or organization have agreed in writing in a contract or agreement" that they be added. It also covers any other party that contract requires you to add, which is how the operator's co-owners, affiliates, or other contractors in its group can come along. Many oilfield policies use the insurer's own blanket wording instead of the ISO form, usually phrased along the lines of "where required by written contract."

This is the gap that catches the most contractors.

Ongoing operations coverage protects the operator for claims arising while your work is underway. Both CG 20 10 and CG 20 38 are written this way, and both exclude injury or damage occurring after your work on the project is completed or put to its intended use. CG 20 38 says status as an additional insured "ends when your operations for the person or organization... are completed."

Completed operations coverage protects the operator for claims that show up after you leave, for example a flowline connection you made that fails months later. That takes a separate endorsement such as CG 20 37, which covers injury or damage caused by "your work" that falls within the products-completed operations hazard.

Most MSAs ask for both. If your certificate shows a blanket ongoing operations endorsement only, expect it to fail review.

Every blanket form depends on a contract. The ISO wording requires that you and the other party "have agreed in writing." Some insurers' blanket endorsements go further and require that the contract be signed before the injury or damage happens. Read your own form for that detail.

What this means on the ground:

• An MSA that is still sitting unsigned in someone's inbox may not trigger coverage.
• A verbal promise to "add them" does not trigger blanket coverage.
• Work orders that reference an MSA should point to one that is actually executed.

The forms also limit coverage to what the contract requires. CG 20 38 says the coverage "will not be broader than that which you are required by the contract or agreement to provide," and the most the insurer will pay for the additional insured is the lesser of the limits the contract requires or the limits available on your policy. So the insurance language in the MSA quietly shapes the operator's coverage.

Additional insured status is usually one item on a list. The MSA will often also require primary and non-contributory wording (CG 20 01 on a standard GL policy) and a waiver of subrogation. The umbrella should follow the additional insured status on the GL, and the auto policy has its own additional insured mechanics.

The ISO additional insured forms also say the coverage "only applies to the extent permitted by law." In Texas oilfield work that connects to the Texas Oilfield Anti-Indemnity Act, which is why the indemnity clause and the insurance exhibit should always be read together.