Pierre Gasly finished third in the Saturday Sprint at the Belgian Grand Prix but the Alpine driver said he had been unable to see much in the spray and had not felt safe.
Racing at speed in wet conditions and limited visibility is a major current safety concern in Formula One after the deaths of two junior drivers in the space of four years at Spa-Francorchamps.
One was Gasly's close friend and compatriot Anthoine Hubert in a 2019 Formula Two race. The other, 18-year-old Dutch driver Dilano van 't Hoff, was killed in a crash this month.
"I could not see a thing," Gasly told reporters after finishing behind Red Bull's championship leading race winner Max Verstappen and McLaren's Oscar Piastri.
"If Oscar or Max was in the middle of the straight, I would have been straight inside him. I just couldn't even see 10, 20 metres ahead of me.
"You're just hoping for the best, but I didn't feel safe."
The field did five laps behind the safety car to displace standing water before a rolling start. The safety car was deployed again on lap three when Aston Martin's Fernando Alonso crashed. Gasly said the spray remained a problem.
"At the moment it’s so huge out of these cars, the water just stays in the air," he added.
"You want to race but at the same time I'm glad everything went safely today. But all you need is just one guy to be stopped at the wrong place in the straight and it can go wrong very quickly. So it's a tricky call."
Verstappen recognised Gasly's concerns, and recalled races in his own junior career where he could see nothing ahead.
"Also today, for example, I couldn't even see the Safety Car sometimes and I'm the first guy," he added.
Mercedes team boss Toto Wolff said the race direction had got it right.
"You can absolutely understand that everyone needs to play it safe here in Spa, we had two terrible accidents and the last one under similar conditions in the rain where drivers couldn't see because of the spray," he said.
"So it was clear that the approach here needed to be on the super-safe side, and I think that was right. The spray on the new Tarmac is pretty bad."
Wolff said Spa, a landmark in the sport with the famed sweep of Eau Rouge, had a place on the calendar but with improved safety.
"Some of these corners are what makes Formula One, but the cars are very quick and the spray is very bad," he said.
"What is it we can all do jointly to keep the absolutely brilliant racetrack here on the calendar whilst making sure there is more visibility in the rain?"
