Section 4: Unanticipated Hazardous Materials Encountered during Construction

This section covers unanticipated hazardous materials that may be encountered during construction activities, after the contract has been awarded.

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Identifying and recognizing existing hazardous materials is the first act to trigger action. During excavation, indicators of possible contamination include, but are not limited to:

  • rusted barrels and containers
  • stained or discolored earth, as contrasted to adjoining soil
  • fill material containing debris other than construction-related items
  • household trash covered by earth or other material that appears to be interspersed with industrial debris
  • gasoline smells or other odors that emanate when the earth is disturbed
  • oily residue intermixed with earth
  • sheen on groundwater
  • cinders and other combustion products like ash.

Structures such as abandoned oil & gas lines, asbestos cement (transite) pipe and underground storage tanks also require special handling when disturbed.

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Notification and Coordination

The contractor usually discovers unanticipated hazardous materials/waste. When the contractor or TxDOT staff member encounters materials that, upon visual observation or smell, seem likely or possible to contain hazardous materials, he/she must notify the project/area engineer immediately.

The engineer must take the following notification and coordination steps to deal with hazardous materials after discovery:

  1. Once notification is received, confirm or evaluate whether special provisions are needed. The engineer may contact ENV for assistance in contracting for statewide environmental engineering consultant services.
  2. Develop requirements and secure the suspected area for worker and public safety as needed. If possible, relocate the contractor on the project to avoid or minimize construction downtime.
  3. Notify ENV-PPA and the District Construction Office.
  4. Determine applicable regulations; ENV-PPA can assist. If notification is required or additional regulatory assistance desired, the District Construction Office should notify the local office of the TCEQ. ENV-PPA is available to facilitate communication and coordination with the TCEQ.
  5. If possible or practical, identify and notify the responsible parties for preventive action and/or cost recovery.

When hazardous materials are discovered, TxDOT assumes responsibility for testing, removal or disposition. The standard provisions of the contract address compensation to the contractor for delays and work stoppages. In accordance with Item 4.2 of the TxDOT Standard Specifications, the contractor should be given the option to perform the testing, removal and/or disposition as "extra work" by a Change Order(s). The engineer may need to obtain proposals and estimated costs for "extra work" from consultants and/or specialty contractors to compare with the estimate from the contractor. If the “extra work” is not an option, work should be suspended wholly or in part through proper notice to the contractor. If possible, re-deploy the contractor on the construction project to avoid or minimize construction downtime.

Another option is to arrange for an emergency contract for a specialty contractor. Some districts may have prearranged purchase orders for specialty contractors and/or laboratories. An environmental consultant may be necessary for testing or developing preventive action plans. ENV-PPA can provide statewide environmental engineering consultants and further assistance as needed.

Coordinate between CST, DES, ENV-PPA, the prime construction contractor, specialty subcontractor, environmental consultant, responsible parties and other agencies. At this time, consider "partnering" to reduce the possibility of future claims.

Coordinate the implementation of preventive action with the construction activities of the project. This may involve concurrent activities by consultants, specialty contractors and the prime construction contractor/subcontractors.

If work is suspended, then the District Construction Office and engineer will issue a "notice of resumption of suspended work" to the prime construction contractor when preventive action is completed.

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Characterize the Contaminant and Develop Preventive Action Plan

It may be necessary for the prime construction contractor or TxDOT to hire a consultant to identify and characterize the contamination through sampling and analytical testing. The objectives of the consultant's investigation include:

  • determining characteristics of the soil, groundwater and vapor, including groundwater recovery rates, vertical/horizontal extent of contamination and chemicals of concern
  • assessing worker safety and public exposure concerns
  • determining handling and/or disposal requirements for any contaminated media unearthed during the construction process
  • recommending a preventive action plan to ensure the problem is not aggravated and to avoid or minimize department liability
  • determining necessary requirements to allow the prime construction contractor to resume work following suspension.

Consultants may also develop specifications to complete portions of the construction within contaminated environments. Data obtained from the investigation will enable the consultant to develop specifications related to groundwater treatment or filtration systems, ventilation systems, ongoing site monitoring, contaminated material disposal/reuse options and permitting. Environmental consultants can be procured through the statewide engineering and environmental consultant program administered by the CSS, with technical oversight provided by ENV-PPA.

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As discussed earlier, the District Construction Office and the engineer are primarily responsible for generating and maintaining a thorough record. Appropriate reports close out the preventive action part of the work; a proper resumption order restarts the construction. The engineer completes the records by carefully noting all the actions taken from the time the initial notification was received up to closure with regulatory agencies.

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