An 80-year-old bus driver was allegedly attacked by a petrol station worker after asking for a £30 fuel limit to be removed.
Keith Murgatroyd’s daughter Sophie told the BBC an employee at an Esso forecourt “punched him in the back of the head” after refusing his request to put more fuel in his school coach.
She said her dad, from Harrogate, was left bleeding after the incident, adding it was her "worst nightmare" to learn something had happened to him.
North Yorkshire Police confirmed an investigation is ongoing and a man is "helping them with their enquiries", but no charges have been brought.
A spokesman for the station, which is run by Euro Garages, said it takes customer safety "very seriously" and is looking into the incident.
Sophie, 31, from Knutsford, told CheshireLive when her father went outside to walk back to his coach to get his wallet so he could pay for £30 worth of fuel, the employee followed him before attacking him.
She claimed the man continued to punch her father before customers, including a man and a couple, "dragged him off".
Sophie, a commercial solicitor, said she got a call from the witnesses and the police about the attack and then rushed to his home, where she is currently looking after him.
Many garages have been running dry following a chaotic week of panic-buying, fights at the pumps and drivers hoarding fuel after a lack of truckers strained supply chains.
Sophie said: "I know it's a really stressful period for everybody at the minute, but I cannot come up with a situation ever where someone would do that to an 80-year-old man looking to get his wallet out of his coach to take children to school.
"I can't comprehend that. I can't process it at all."
Sophie added: "Getting a call to say your father has been attacked is every daughter's worst nightmare. He is 80 years old.
"Although I am emotionally driven by this, there is also a moral obligation to ensure this does not happen to anybody else."
A Euro Garages spokesperson said: "We take issues of colleague and customer safety very seriously and we are looking into this in line with our internal policies and procedures ‒ as a matter of the utmost priority."
A spokesperson for North Yorkshire Police said: "A man is helping police with enquiries following the incident and the investigation is ongoing. Currently no charges have been brought."