Ashland Chemical, a hazardous waste warehousing business in Binghamton, will begin an investigation to see whether pollution at the site is affecting nearby properties, a health official said Tuesday.

The ground beneath the hazardous waste storage company on Broad Street is polluted with trichloroethylene (TCE) that could be forming gases and pushing into basements of nearby properties, said Ron Brink, an official with the Broome County Department of Health.

The company, overseen by state health and environmental agencies, will begin testing soil and properties within a two- to three-block area around the site, Brink said.

"There is going to be a very thorough investigation in and around those houses," Brink told a group of residents and advocates at a meeting Tuesday evening at Endicott's First United Methodist Church.

Letters and a fact sheet are being sent to nearby property owners advising them of the plans for the investigation.

Vapor intrusion has affected more than 480 properties in Endicott, more than 70 in Hillcrest, 25 in Norwich and an undetermined number in Vestal and Binghamton.

A vast industrial legacy, porous geology, extensive aquifers and old homes with porous foundations create conditions that help solvents move through the ground, making some places in the Southern Tier prone to the problem.

"The biggest concern is the geology. It's very sandy and gravely. There is the potential for TCE to make its way into houses," Brink said.

Exposure to the chemicals raises the risks of illnesses ranging from rashes to cancer.

But levels are a matter of scientific debate.

State and federal governments are developing regulations.