Two members of the plant's fire unit were killed in a blast which occurred at around 11:30 am (0930 GMT) on Monday
Firefighters on Monday evening extinguished a blaze at a BASF chemical plant in western Germany where two colleagues were killed in a major blast, a company spokesman said on Tuesday.
A third individual is missing after the incident, whose causes remain unknown.
"Small but constant amounts" of liquefied ethylene or propylene gas were still leaking from at least one breached pipe at BASF's Ludwigshafen home base and hindering cleanup work, site manager Uwe Liebelt said.
City fire chief Peter Friedrich told reporters that firefighters had swathed the pipework with foam coolant to hinder further blazes breaking out.
Two members of the plant's fire unit were killed in a blast which occurred at around 11:30 am (0930 GMT) on Monday.
Their team had been called out to a fire near a dock, where liquids and liquefied gases are transferred into tanks from ships on the Rhine, before they were caught in the explosion.
Six people remain in intensive care with severe burns.
The explosion destroyed firefighters' vehicles and sent a plume of black smoke high into the sky above the riverside towns of Ludwigshafen and Mannheim.
A further 17 people were slightly injured, while one person is still missing.
Firefighters from both towns and BASF fought to get the flames under control until they were finally extinguished late on Monday evening.
"By tomorrow (Wednesday) evening we should be able to begin further clearing operations," including pumping away the flammable liquefied gases still leaking from a 300-metre (yard) stretch of pipe, Liebelt said.
The leaking gases make it too dangerous for divers to enter the harbour basin in search of the missing person, fire chief Friedrich said.
Prosecutors and police are already investigating parts of the scene that have so far been declared safe.
Workers had been cutting and welding an empty pipeline in the area for several days, Liebelt said, although he added that "we have no knowledge of how the first fire started".
Company and city officials repeated advice to local people to remain inside and keep doors and windows closed, although they insisted no dangerous levels of chemicals had been measured in the air around town or in river water.