The biggest advertising organizations say Apple will “sabotage” the current economic model of the internet with plans to integrate cookie-blocking technology into the new version of Safari.

Six trade groups—the Interactive Advertising Bureau, American Advertising Federation, the Association of National Advertisers, the 4A’s and two others—say they’re “deeply concerned” with Apple’s plans to release a version of the internet browser that overrides and replaces user cookie preferences with a set of Apple-controlled standards. The feature, which is called “Intelligent Tracking Prevention,” limits how advertisers and websites can track users across the internet by putting in place a 24-hour limit on ad retargeting.

In an open letter expected to be published this afternoon, the groups describe the new standards as “opaque and arbitrary,” warning that the changes could affect the “infrastructure of the modern internet,” which largely relies on consistent standards across websites. The groups say the feature also hurts user experience by making advertising more “generic and less timely and useful.”

“Apple’s unilateral and heavy-handed approach is bad for consumer choice and bad for the ad-supported online content and services consumers love,” according to a copy of the letter obtained by Adweek this morning. “Blocking cookies in this manner will drive a wedge between brands and their customers, and it will make advertising more generic and less timely and useful. Put simply, machine-driven cookie choices do not represent user choice; they represent browser-manufacturer choice.”

Of course, the digital advertising world has a lot to lose if hyper-targeting becomes more diluted. According to an eMarketer report released in March, digital ad spending in the U.S. is expected to reach $83 billion in 2017, up nearly 16 percent from last year.

When Apple first announced the limitations to cross-website tracking in June, the company said the changes are meant to improve trust with users, explaining that “users feel that trust is broken when they are being tracked and privacy-sensitive data about their web activity is acquired for purposes that they never agreed to.” In a statement emailed to Adweek regarding the industry groups’ letter, Apple reiterated the importance of consumer privacy while also pointing out Safari was the first browser to block third-party cookies by default even before the introduction of Intelligent Tracking Prevention. (According to Apple, Intelligent Tracking Prevention will still allow tracking on websites a person visits.)

“Ad tracking technology has become so pervasive that it is possible for ad tracking companies to recreate the majority of a person’s web browsing history,” according to an Apple spokesperson. “This information is collected without permission and is used for ad re-targeting, which is how ads follow people around the Internet.”

While the Safari updates detect and eliminate cookies and other data, it doesn’t block actual ads. (Google, however, is already testing an ad blocker for Chrome which could be released more broadly next year.)

While the trade groups criticized the move by Apple, some industry experts said the latest feature is a welcome addition.

“Intelligent Tracking Prevention uses machine learning to block companies with no relationship with consumers from employing cross-site tracking work-arounds,” said Jason Kint, CEO of Digital Content Next, an online publishing group. “While this may not be a perfect solution, I applaud Apple’s efforts to more closely align with context and consumer expectations.”

Here’s a full copy of the letter, which was also signed by the Data and Marketing Association and the Network Advertising Initiative:

September 14, 2017 An Open Letter from the Digital Advertising Community The undersigned organizations are leading trade associations for the digital advertising and marketing industries, collectively representing thousands of companies that responsibly participate in and shape today’s digital landscape for the millions of consumers they serve. We are deeply concerned about the Safari 11 browser update that Apple plans to release, as it overrides and replaces existing user-controlled cookie preferences with Apple’s own set of opaque and arbitrary standards for cookie handling. Safari’s new “Intelligent Tracking Prevention” would change the rules by which cookies are set and recognized by browsers. In addition to blocking all third-party cookies (i.e. those set by a domain other than the one being visited), as the current version of Safari does, this new functionality would create a set of haphazard rules over the use of first-party cookies (i.e. those set by a domain the user has chosen to visit) that block their functionality or purge them from users’ browsers without notice or choice. The infrastructure of the modern Internet depends on consistent and generally applicable standards for cookies, so digital companies can innovate to build content, services, and advertising that are personalized for users and remember their visits. Apple’s Safari move breaks those standards and replaces them with an amorphous set of shifting rules that will hurt the user experience and sabotage the economic model for the Internet. Apple’s unilateral and heavy-handed approach is bad for consumer choice and bad for the ad-supported online content and services consumers love. Blocking cookies in this manner will drive a wedge between brands and their customers, and it will make advertising more generic and less timely and useful. Put simply, machine-driven cookie choices do not represent user choice; they represent browser-manufacturer choice. As organizations devoted to innovation and growth in the consumer economy, we will actively oppose any actions like this by companies that harm consumers by distorting the digital advertising ecosystem and undermining its operations. We strongly encourage Apple to rethink its plan to impose its own cookie standards and risk disrupting the valuable digital advertising ecosystem that funds much of today’s digital content and services. Signed, American Association of Advertising Agencies (4A’s) American Advertising Federation (AAF) Association of National Advertisers (ANA) Data & Marketing Association (DMA) Interactive Advertising Bureau (IAB) Network Advertising Initiative (NAI)

UPDATE: This story has been updated to include a statement from Apple regarding the ad industry groups’ letter.