Google-owned YouTube shook up its Measurement Program on Monday, adding several new companies to its roster of approved vendors while also excluding one longtime partner after it refused to sign a contract that would limit what it can and cannot report to its clients.

The YouTube Measurement Program (YTMP) was created in 2017 and gives approved third-party vendors access to its treasure trove of data through an API. These companies in turn use that data to sell brands and agencies services in areas such as measurement or brand safety.

“You are talking about billions of views—that is what the API brings to the table,” says Jed Hartman, chief commercial officer at Channel Factory, an approved YouTube Measurement partner. “What you do with that data is essential.”

OpenSlate was among the five initial companies included under YTMP when it debuted in 2017, but was notably absent from the list of updated vendors. The company is refusing to sign a contract with YouTube, which, under the terms, would prevent it from reporting whether ads ran next to videos with questionable or harmful content, such as those that include profanity, illegal substances or violence, according to an executive familiar with the negotiations.

Under the new contract, OpenSlate is allowed to tell clients if their ad ran next to a video about soccer, but couldn’t say the video is part of a YouTube channel that’s historically shared violent content, the person says. As a result, the company is questioning the value YouTube’s Measurement Program provides marketers, claiming the new restrictions defeat the program’s intended purpose. OpenSlate clients include Procter & Gamble, Nestle and GroupM. The company is perhaps best known for providing brand safety tools after raising its profile three years ago during YouTube’s brand safety debacle.

“Advertisers rely on OpenSlate's independent, third-party measurement to ensure they are running in suitable environments,” OpenSlate told Ad Age in an email statement. “Google is a valued partner and we endeavor to resolve our differences.”

Google declined to comment when specifically asked about OpenSlate, citing its policy during active negotiations, but says it’s important that the industry has “a healthy third-party ecosystem.”

“We’re excited to expand the YouTube Measurement Program and look forward to working with the nine partners who have already signed on,” a Google spokesman said in an emailed statement. “We also remain open to any other third parties who help meet our clients’ needs joining the program in the future.”

YouTube in the meantime is pressing forward with its Measurement Program by adding new companies DoubleVerify, Integral Ad Science, Channel Factory, Sightly and VuePlanner to its roster of approved vendors. The companies will each be placed under one of three newly created specializations: brand suitability and contextual targeting, content insights and brand safety reporting.

DoubleVerify and Integral Ad Science will operate under the “brand safety reporting” category; Channel Factory, Pixability, Sightly, VuePlanner, Zefr and IAS will fall under “brand safety suitability and contextual targeting”; while Pixability, Tubular Insights and Wizdeo are now included under YouTube's “content insights” category.