If you have been hurt on the job in California, you already know that getting timely medical care through workers’ compensation can feel like a maze. You get a stack of paperwork from the claims administrator, a list of doctors you may or may not be able to see, and vague references to something called a Medical Provider Network, or MPN. When care gets delayed or denied, most injured workers do not know whether the insurer is following the rules or bending them.
A new law changing the 2026 landscape gives workers a clearer footing. AB 1048 targets one of the most common breakdowns in workers’ comp claims: unclear MPN notices that make it hard to verify whether a doctor is authorized, whether the network is valid, and whether your treatment is being properly routed. Below, we walk through what the new rules require, why they matter for your claim, and how to push back when the paperwork is vague or missing key details.
What AB 1048 Actually Requires
According to Keenan’s 2026 mid-session legislative summary, AB 1048 tightens the disclosure rules on explanations of review, sometimes called EORs, and explanations of benefits sent to providers and injured workers. Under the new requirements, those documents must include the MPN identification number and specific contact information that a provider can use to request a copy of the underlying contract between the provider and the network.
That may sound like a technical accounting change, but it has real consequences for injured workers. MPN transparency has been a persistent complaint in the California workers’ comp system. Providers get denied payment on the theory that they are or are not in a network, workers get steered away from doctors they thought were authorized, and no one can easily verify the chain of authority behind the denial. AB 1048 forces the paperwork to speak plainly about which network is being invoked and how to check the underlying contract.
For injured workers, the practical upshot is this: if you receive a denial, a treatment redirection, or a payment dispute tied to network status, the notice itself must now give you and your provider the tools to verify it. If those tools are missing or inaccurate, that is a compliance problem the insurer or employer will have to answer for.
Why MPN Disputes Delay Care in the First Place
Medical Provider Networks are groups of physicians pre-selected by the employer or its insurer to treat work injuries. In theory, MPNs streamline care and control costs. In practice, they often become chokepoints that slow down treatment for exactly the workers who most need it.
Common MPN problems we see include doctors listed as in-network who no longer accept new workers’ comp patients, physicians whose specialties do not actually match what the injured worker needs, notice packets that never reach the worker in a language they can read, and referrals to specialists that are quietly denied because the specialist is not on the current MPN roster.
John Reardon spent 20 years as a chiropractor before becoming a lawyer, and during those two decades he saw the MPN problem from the inside. Injured workers would arrive at his office with a diagnosis, a course of care, and a claims adjuster telling them they had to switch providers because of a network technicality. Some of those redirections were legitimate. Many were not. When a worker with an acute lumbar disc injury is bounced between three different providers over eight weeks, the medical damage compounds. Muscle guarding sets in, range of motion decreases, and the window for conservative treatment narrows. That is not a paperwork problem. That is a patient outcome problem.
AB 1048 does not fix every MPN failure, but it forces the paperwork to be legible enough that workers and their attorneys can actually spot the failure and challenge it.
What Your MPN Notice Should Contain
If you are receiving treatment under a workers’ comp claim in California, the notices you get from the claims administrator or the network itself should give you enough information to verify your rights. Under AB 1048 and existing regulations under Labor Code section 4616 and the associated rules in Title 8 of the California Code of Regulations, a proper MPN notice generally needs to identify:
- The name of the MPN and its identification number
- Contact information for the MPN medical access assistant
- Instructions on how to find in-network providers, including a current provider list
- Your right to a second and third opinion within the network
- Your right to request an independent medical review in certain circumstances
- Contact information a provider can use to request the underlying contract between the provider and the network
If your notice is missing the MPN identification number, does not tell your provider how to verify the contract, or is written in a way that makes the appeal process unclear, that is a red flag. It may mean the notice is not compliant, and non-compliance can shift the leverage in your claim.
How Non-Compliant Notices Strengthen Your Position
California case law has long recognized that when an employer or insurer fails to give proper MPN notice, the worker may be entitled to seek treatment outside the network at the employer’s expense. Decisions like Knight v. United Parcel Service and later Workers’ Compensation Appeals Board panel decisions have made clear that MPN control is not automatic. It has to be earned by following the notice and access rules to the letter.
AB 1048 adds a new layer of specificity to what those notices must contain. That gives injured workers and their attorneys a cleaner argument when notices are vague or incomplete. If you can show that the EOR or benefits explanation did not include the MPN identification number, or did not tell your provider how to obtain the network contract, you may have a credible argument that:
- The employer or insurer has not properly established MPN control over your care
- You are entitled to select a treating physician of your choice
- Prior denials tied to network status should be reconsidered
- The delay in care caused by the improper notice should be considered when evaluating temporary disability, permanent disability, and future medical needs
None of this happens automatically. You or your attorney has to raise the compliance issue, document the deficiency, and force the insurer to justify its position. That is where preserving records becomes critical.
A Practical Checklist for Injured Workers
Whether or not you already have an attorney, there are steps you can take right now to protect your rights under the new rules.
1. Keep every piece of paper. Every EOR, every denial letter, every notice about your MPN, every provider list. Do not throw anything away, and do not rely on the insurer to keep a complete file for you. Scan or photograph documents as they arrive.
2. Note the dates. When did you receive the initial MPN notice? When did you first ask for a provider list? When did you request a change of physician? Timelines matter enormously in workers’ comp disputes.
3. Verify each notice against the new AB 1048 requirements. Look for the MPN identification number and the provider contact information for requesting the network contract. If either is missing, flag it.
4. Ask for the network contract information in writing. If your provider is being told they are out of network or that payment is denied on network grounds, have them request the underlying contract through the channels the notice is supposed to provide. If those channels do not work, that is evidence.
5. Document treatment delays. Every time care is delayed because of a network dispute, note the date, the reason given, and the impact on your symptoms. From a medical documentation standpoint, treatment gaps caused by administrative disputes should be attributed clearly to those disputes, not to your condition.
6. Do not assume a denial is final. Denials tied to network status are frequently overturned when the paperwork is scrutinized. If your care is being redirected or refused, get a second opinion from an attorney before accepting the outcome.
When to Push Back and How
If you believe the MPN rules are being used to delay or divert your care, there are formal mechanisms available. You can request an expedited hearing at the Workers’ Compensation Appeals Board on medical treatment disputes. You can request independent medical review on utilization review denials. And in cases where the MPN itself was never properly established, you may be able to treat outside the network entirely and require the insurer to pay.
Choosing the right procedural tool depends on the facts. An expedited hearing is faster than a full trial but has its own evidentiary rules. Independent medical review is limited to specific types of treatment disputes. Challenging MPN validity requires a factual record about what notices you received and when.
This is one of those situations where the technical background matters. When John Reardon reviews a workers’ comp file, he reads it as a former treating provider and as an attorney. He can tell when a course of care was medically appropriate but got interrupted by administrative decisions, and he can translate that into the kind of documentary record the appeals board takes seriously.
Talk to Us Before the Next Denial Letter Arrives
AB 1048 is not going to eliminate MPN disputes, but it does give injured workers real leverage when the paperwork falls short. The workers who benefit most from these rules are the ones who spot the problems early, preserve their records, and get advice before they sign away rights or accept a denial at face value.
If you are dealing with a California workers’ comp claim and you suspect the network rules are being used to slow down or steer your care, we would like to help you sort it out. Our consultations are free, and there is no obligation. Call Reardon Injury Law and we will review your notices, your treatment history, and your options for pushing back.