The leak closed the Delaware Memorial Bridge for eight hours on Sunday night during the busy Thanksgiving Day weekend as government officials assessed the situation.
Croda said it will not manufacture ethylene oxide until the company and state officials "are confident that the plant can resume safe operations."
"We are sending this gasket to independent experts for analysis and confirmation. Our findings show that no other damage occurred to the ethylene oxide plant,” the company said in a statement.
Shawn Garvin, secretary of the Delaware Department of Natural Resources and Environmental Control, said on Monday there were two main threats: People nearby who could have inhaled the ethylene oxide and the EO could have caught on fire and spread to the vehicles on the nearby interstate.
Croda officials also said they will conduct a "systematic review of all other equipment on the ethylene oxide plant pipework," a process that is expected to take about two weeks.
"We are committed to understanding what went wrong, so we can prevent such an incident happening again," the company said.