BOSTON (AP) — The operator of seven Burger King restaurants in western Massachusetts has been fined $50,000 for violating state child labor laws.

The state attorney general’s office said Friday that the fine assessed against MHC Services LLC of West Springfield was for multiple violations between May 2009 and October 2011.

The state started investigating after a tip and found that the company’s restaurants employed minors later than 10 p.m. on school nights and later than midnight on weekend nights, both child labor law violations. The state says the company’s restaurants also allowed minors to work hours beyond state-set daily limits.

The attorney general’s office says MHC cooperated and has changed procedures to stay in compliance with the law.

A phone call left for an MHC official was not immediately returned.

Copyright 2012 The Associated Press.