A firefighters union in a Sacramento, California suburb was under fire Sunday after placing an assault rifle up for auction at a fundraising event Saturday night.

Some attendees walked out of the Cameron Park Firefighters Association crab feed when they saw an AR-15, similar to the one used in a mass shooting at a Florida high school just days ago, sitting on the auction table.

"These are our first responders responding to these types of events, these shootings, and they should be concerned with putting one of those types of weapons out in our community," attendee Allison Merrill said. "And instead, it was being given out as a prize."

Another woman who walked out in protest, Nancy Lugo, said the timing of it couldn't have been worse.

The Cameron Park Fire Department is under contract with Cal Fire.

"This was a fundraising effort that has taken place since 2002," Cal Fire spokesman Scott McLean said. "I understand the concerns, by all means. No harm was intended."

The union refunded the woman's money for the crab feed.

"The money wasn't really an issue," Merrill said. "I just wanted him to know we were leaving in protest, that it was totally tone deaf of them to have that, especially given the timing."

Firefighters said the auction was planned before the rampage in Florida, and the winning bidder will still have to pass a background check before taking ownership of the weapon.

Cameron Park is located about 32 miles east of Sacramento in El Dorado County.