PCB contamination

Researchers at Harvard School of Public Health in the US have identified caulking and sealing materials as an unrecognised and possibly widespread source of PCB contamination.

Environmental health researchers at Harvard School of Public Health (HSPH) in the US have identified caulking and sealing materials as an unrecognised and possibly widespread source of polychlorinated biphenyl (PCB) contamination in schools and buildings constructed in the 1960s and 1970s.

They conclude that a survey of masonry buildings from that era is necessary to determine where in the US these materials had been used, and that caulking should be routinely analyzed for PCBs and managed appropriately to reduce potentially significant health risks.

PCBs are a set of persistent organic chemicals that are known carcinogens and that have significant toxic effects on the immune system, reproductive system, nervous system and endocrine system. Production of PCBs was halted in the US in 1977, but they persist in the environment.

Although the principal use of PCBs was in ‘closed systems’ such as electrical transformers, capacitors and other equipment where the PCBs were encased, they were also used in a range of ‘open system’ products, including building materials.

HSPH researchers led by Robert Herrick, Senior Lecturer on Industrial Hygiene in the Department of Environmental Health, carried out an investigation of 24 buildings in the Greater Boston Area.

The investigation revealed that one-third of the buildings contained caulking materials with PCB content exceeding US Environmental Protection Agency standards of 50 parts per million, in some cases containing nearly 1,000 times the standard. The buildings where elevated PCB levels in caulking were found included schools, university buildings and other public buildings.

The investigation was prompted by studies done in Finland and by the recent case of a University of Rhode Island building that was found to be contaminated by caulking material containing PCB concentrations 600 times higher than the EPA limit and which resulted in an EPA-mandated cleanup program.

Studies in Finland have correlated PCB content in caulking with PCB content in the air and in the blood of construction workers handling these materials during renovation work. A German study found elevated blood levels of PCBs in teachers working in school buildings with contaminated caulking. Finland has gone so far as to remove these caulking materials from all buildings in the country, and Sweden is preparing rules for a similar abatement.

‘At the time of construction of these buildings in the 60’s and 70’s, this material was commonly used,’ said Herrick.

It is the rubbery, flexible material you see around windows in masonry buildings. The EPA banned PCBs in 1977 but has not required that caulking be tested to determine PCB content, so the extent to which this material is still in buildings is unknown. After 30 years, these materials are deteriorating, and just touching them may cause exposure.

The researchers said that their limited investigation into two dozen buildings in Boston strongly suggests that were this testing done, many buildings would be found to contain high levels of PCBs in the building materials and potentially in the building environment.

The presence of PCBs in schools is of particular concern given evidence suggesting that PCBs are developmental toxins.

‘We have made progress in reducing PCB uptake by advising people to reduce their consumption of contaminated fish and other foods,’ said Herrick, ‘but the contribution to the PCB body burden from living and working in PCB contaminated buildings is largely unrecognised.’

The situation is very similar to lead in paint, where a material used in building construction leads to contamination of the building interior and the soil around the buildings. This is of special concern as the studies in Finland found that children’s play areas were located in areas of high soil PCB contamination near buildings containing these caulking materials.