Salesforce has a problem on its hands, with a growing number of employees expressing their disapproval of the company’s ties to the National Rifle Association (NRA).

In the wake of multiple mass shootings, Salesforce employees are taking the company to task for having the NRA as a customer. According to Business Insider, some 4,000 employees have signed an open letter demanding the company sever ties.

“It’s not in our power to get background checks or other gun control measures passed by Congress — but we can effect change by ending our commercial relationship with our customer, the National Rifle Association,” the Salesforce employees wrote in their letter.

The employees are hoping to prevail on co-CEO Marc Benioff, who has expressed support for increased gun control in the past. The employees are concerned over the prospect of the NRA using the Salesforce platform for continued fundraising and marketing efforts.

“It is unconscionable to consider their use of Marketing Cloud to capitalize on mass shootings,” the letter continued.

It’s unclear if Salesforce’s leadership will follow through on the letter’s demands, but the situation illustrates the ethical challenges companies are increasingly facing as employee activism continues to grow.