Kaua'i firefighters evacuated workers from businesses in Lihu'e Industrial Park II yesterday after a hazardous chemical leaked during a transfer operation in a warehouse.

They expected the cleanup to continue into the night and were unsure whether the industrial park would reopen this morning.

Firefighters said the spill of methyltrichlorosilane — a highly flammable chemical that, according to the Centers for Disease Control and Prevention, can cause breathing problems when inhaled, and burns and irritation when touched — occurred at about 8:30 a.m.

An employee of Trex Hawai'i LLC was transferring methyltrichlorosilane from a storage tank to a process tank in the company's Aukele Street warehouse. Dave Kane, vice president of Kaua'i operations for Trex Hawai'i, said a faulty valve on the storage tank caused the chemical to leak during the transfer.

He said the worker, who was wearing protective gear and was not harmed, immediately left the bunker and closed the door to contain the spill.

Firefighters, hazardous-materials technicians, police and a state health official gathered at the site soon after being notified.

Shortly after 11 a.m., a hazardous-materials team entered the bunker and sprayed foam into it to prevent vapors from escaping. By 2:45 p.m., after taking air quality tests around the building, firefighters allowed Trex Hawai'i officials in to assume responsibility for the situation.

Technicians from O'ahu-based PENCO were contracted to handle the neutralization of the hazardous material and flew to Kaua'i yesterday afternoon.

Lihu'e Industrial Park II will remain closed until it is deemed safe for the public and workers to return.

Reach Karen Blakeman at kblakeman@honoluluadvertiser.com.