An internal investigation of Craig Field auto supplier Renosol didn’t find any excessive traces of dangerous chemicals.

Renosol’s parent company — the Lear Corporation — announced internal investigations results Wednesday — one day after the Occupational Safety and Health Administration officially opened an investigation into the plant.

As part of the internal investigation, Lear Vice President of Environmental Health and Safety Barbara Boroughf said an industrial hygienist conducted multiple sampling tests for TDI, MDI and mold during the plant’s normal operations.

“There were no significant abnormalities,” Boroughf said. “As required by law, employees will receive the results and the results will be posted in the plant.”

TDI can cause decreases in lung function and asthma-like reactions, according to the Environmental Protection Agency. MDI has similar effects, but also irritates skin and eyes in high concentrations, according to the EPA. Both chemicals are used to create car seats in Renosol’s Craig Field plant.

The investigation stems from a May 8 letter that employees delivered to Renosol’s human resource manager. The letter stated employees were excessively exposed to TDI. Employees said exposure caused 75 percent of the plant’s workers to develop asthma-like symptoms.

Lear officials declined to speculate on the employees’ claims after the internal investigation’s results.

“Anything we say might be speculation, but if our employees have a concern we take them at face value,” Lear Senior Vice President Tom DiDonato said.

In announcing results of their investigation, Lear officials also addressed employees concerns about recent, frequent sounding of monitoring alarms.

After delivering the letter on May 8, Renosol employee Kim King said monitoring alarms sound frequently and could signal high concentrations of TDI in the plant.

Lear senior vice president Mel Stephens said alarms could sound for a number of reasons, but function as an early warning mechanism.

“The fact that the alarm goes off doesn’t mean any danger,” Stephens said.

King and Stephens both said employees are evacuated immediately following an alarm.

Results from the OSHA investigation are still pending. An OSHA representative was in the Renosol plant Tuesday because of the agency’s investigation. Boroughf said OSHA’s investigation should conclude in three weeks, but she doesn’t expect any significant findings.

“They will use the same sampling protocol that we used,” she said.

OSHA is a part of the U.S. Department of Labor and was created by an act of Congress in 1970.

The employees’ letter also contained references to long hours and low pay, which Lear officials said they considered a separate issue in a previous interview with the Times-Journal.