The GlaxoSmithKline Consumer Healthcare Manufacturing plant in Aiken remained closed on Wednesday afternoon while crews continued to work on repairs to the sewer system, a spokeswoman said.

Operations at the plant shut down Tuesday morning after a presence of “elevated methane levels” was detected in the sewer system at the site on Windham Road.

“The GSK Aiken site continues to work on repairs to the sewer system,” said Teresa Caro, a spokeswoman for GSK. “Operations will restart when methane levels are back to normal and it is safe for employees to return to work.”

Employees in the plant were evacuated, and other areas of the site were cleared for safety and security purposes, Caro said. Employees are encouraged to check in with the site before leaving for work.

There is no safety risk posed to the surrounding community by the methane levels.

The site employs about 200 people and manufacturers about a dozen pharmaceutical products.