Firefighters in Merseyside are regularly called to "booby-trapped" fires, their union claims.
Firefighters say that the incidents are becoming more regular
The Fire Brigades Union (FBU) says crews have faced razor blades in banisters, holes in floors covered with carpet and "greased" steps.
It claims the incidents, at least 40 reported a week, are so common they are considered an "occupational hazard".
Merseyside Fire Service said it is concerned about the problem, but disputes the number of incidents.
FBU Merseyside Fire and Rescue Service secretary, Les Skarratts, told the BBC firefighters had found staircase rails with embedded razorblades or hypodermic needles and outside steps smeared with axle grease.
Other reported incidents include removed floorboards covered over with carpet.
"It really is a serious issue for firefighters on Merseyside," he said.
"It is common for every firefighter in the area to come across the problem."
A dedicated team to tackle anti-social behaviour, including firefighter attacks, was recently set up by Merseyside Fire and Rescue Service, with Merseyside Police.
The fire service said it receives reports of only two or three incidents a year.
But John McGhee, FBU National Officer, says there is a "poor process" of reporting firefighter attacks, which explains the low official figures.
"It's almost like there is an attitude now that it has almost become part of the job and staff just have to put up with it and don't report it," he said.
He said a recent national survey the FBU carried out showed there are 40 attacks a week on firefighters, but the figures could be as high as 120.
Mr McGhee said he has no real idea why these attacks are happening.
"One reason could be because disaffected youths think that firefighters are part of the establishment and are a fair target because of it," he said.
"We've had some firefighters who have been very seriously hurt - they have been stoned while tackling fires and scaffolding posts have been put through windscreens of fire engines."