PITTSBURG -- A malfunction at a chemical plant caused two small releases of chlorine gas this week and a brief public health advisory from the county Thursday afternoon, but officials said the releases were contained to the plant's property and no injuries were reported.

K2 Pure Solutions stopped production early Wednesday morning after equipment at its chlorine liquefaction plant malfunctioned at 5 p.m. Tuesday and again around midnight, forcing the releases.

The chlorine that leaked earlier in the week pretty much remained on site, Andrews said. No one was injured.

The problems occurred in its heat exchanger, Andrews said.

Leon Zaal, vice president and general manager of K2's Pittsburg site, reiterated that the "business interruption" was a small release, and no one within the community was in harm's way. The company responded "as if it was prepared for the worst," he said.

"Safety is our top priority. Any kind of release is a concern," Zaal said.

Contra Costa Health Services issued a public health advisory around 4:45 p.m. advising residents keep windows and doors closed and consider leaving the area if they have pre-existing respiratory conditions.

There was concern that water had entered into a tank filled with the liquified chlorine, so as they were evaporating the contents, the county put the advisory out in case there was any corrosion that created a leak, said Paul Andrews, a Contra Costa County hazardous materials specialist. The work was completed without incident and the advisory was lifted less than an hour later

The chemical plant on Loveridge Road remains shut down for the foreseeable future, and county hazardous material officials are continuing to monitor the situation.

The K2 plant leases its space on Dow Chemical Co. property along the industrial waterfront. Nonessential workers at Dow were asked not to go to work Thursday as "an abundance of caution," Dow spokesman Randy Fischback said.

The company is also assisting K2 by letting it use its emergency response teams and resources, he said.

K2, which produces industrial bleach and provides Dow with chlorine for its products, is now starting to investigate the cause of the malfunction.

Operations won't restart until the cause is found, Zaal said.

Early examinations of the 5 p.m. incident indicate there may have been some tube failure by a cold-water-based heat exchanger, resulting in some unusually high temperatures, Andrews said, explaining why some thought it was an iron fire at first.

The midnight incident was another heat exchanger farther along in the process, where a vaporizer cools the chlorine, Andrews said.

At this point, K2 has been purging its lines and binding off different parts to make sure all the residual chlorine is out, officials said. After that it can look at what it can replace.

The company is keeping the county's Hazmat team, neighboring industries and officials in Pittsburg and Antioch abreast of its progress.

Zaal said he hopes to have the plant reopened within 24 to 48 hours, though Andrews estimates it could take weeks.

Toronto-based K2 opened its Pittsburg facility on the near-13-acre site in September 2011. They have the capacity to produce about 300 tons of chlorine a day, Andrews said.

K2's Pittsburg plant doesn't have a history of large accidents, though Andrews says that chlor-alkali plants by their nature will have small releases because of the corrosive nature of chlorine.

There have been some minor instances, or what the county calls Level 0 releases, inside K2's facility. There was one incident of a chlorine vapor release last January that got to the property's fence line, garnering some complaints for dock workers at neighboring USS-POSCO.

Contact Paul Burgarino at 925-779-7164. Follow him at Twitter.com/paulburgarino.