A site manager with the Akzo Nobel plant, Henrik Teiffel, calls the leak, which amounted to 32 tons of toxic gas into the water, "very serious." The accident was discovered Thursday morning.
An investigation has been started and the company's environmental experts and toxicologists are analyzing the spread of the chemical and its effect on marine organisms.
The county of Västra Götaland has said it will file a police report against the company for suspected environmental offences, according to news agency TT. It also said it will conduct tests on the water to make sure there are not dangerous concentrations of ethylene oxide or the chemical it dissolves into: ethylene glycol.
An environmental engineer with the county, Elisabeth Lindqvist, told news agency TT that she is not expecting to find hazardous levels.