NTSB eyes aluminum housing covers in derailment investigation

The National Transportation Safety Board is investigating aluminum housing covers on three of the vinyl chloride monomer tank cars in a Norfolk Southern Corp. train that derailed Feb. 3 in East Palestine, Ohio.

Based on damage assessment inspections, NTSB officials are concerned that aluminum protective housing covers on some tank cars melted or were consumed when pressure relief devices (PRD) vented burning gas while functioning as designed to relieve tank pressure.

"Preliminary examination suggests that melted aluminum may have dripped into some PRDs, possibly degrading their performance," officials said March 2.

The derailment happened the night of Feb. 3. Almost 40 rail cars derailed, including five that contained VCM, which is a feedstock for PVC resin. No injuries were reported from the derailment.

Rising temperatures in one of the VCM cars led officials from both Ohio and Pennsylvania — very close to the derailment site — and the railroad on Feb. 6 to drain all five cars and burn off the VCM, resulting in thick black smoke and a chemical odor throughout the area. Officials said that decision was made because of the possibility of an explosion that could have sent shrapnel up to a mile away.

Government and railroad officials have said the air and water have tested safe in most of the area, but local residents — some of whom had been evacuated for three days — remain concerned about their health and the impact of the burnoff.

During the investigation, NTSB investigators discovered that three of the examined VCM tank cars were manufactured in the 1990s with aluminum protective housing covers.

"Although the number of tank cars in flammable gas service with aluminum protective housing covers is presently unknown, NTSB has requested industry data to determine the size of the potentially affected fleet," officials said.

PRD and valve assemblies recovered from the five VCM tank cars are being delivered to a testing facility. During the week of March 13, investigators will examine them to determine the conditions that might have affected their operation following the derailment.

Officials said NTSB is conducting the investigation to determine the probable cause of the derailment and issue any safety recommendations to prevent future derailments. NTSB also can issue urgent recommendations at any point during the investigation, they added.

Environmental Protection Agency officials said March 2 that it has conducted 589 home re-entry screenings to date and continues 24/7 air monitoring at 16 stations.

"There have been no exceedances for residential air quality standards, and outdoor air quality remains normal," they added.

In response to concerns shared by residents, EPA will require Norfolk Southern to sample directly for dioxins under EPA oversight. The agency also will direct NS to conduct immediate cleanup if contaminants from the derailment are found at levels that jeopardize people's health.

EPA also is reviewing an NS plan to remove railroad tracks and excavate contaminated soil at the site. If EPA and the unified command approves, track removal could begin March 3.

The Ohio EPA previously said there is no indication of risk to East Palestine Public Water customers. Treated drinking water shows no detection of contaminants associated with the derailment. They added that the data does not apply to private wells, which should be tested.

A preliminary report from NTSB on Feb. 23 had cited an overheated wheel bearing as the cause of the derailment. A detection system alerted the train's three-person crew to the overheating, according to the report. The train was traveling at 47 mph at the time of the derailment, 3 mph below the speed limit for that type of train.

In a response to the report, officials with Norfolk Southern in Atlanta said the report showed the rail crew operated the train within the company's rules and that wayside heat detectors were operating as designed.

NS has contributed more than $12 million to relief efforts in the area and helped almost 4,000 families, according to the company website. CEO Alan Shaw has made an individual donation of $445,000 to create a scholarship fund for seniors at East Palestine High School.

A list posted online by U.S. EPA of hazardous materials carried by the train showed the five VCM cars, as well as four cars of PVC resin and two cars each of polyethylene and polypropylene resins. Two of the PVC cars were listed as "involved in fire," while one of the cars had burned and the other was still burning, according to the list.

The two cars of PP resin were not involved in the derailment. The status of the two cars of PE resin was unclear. Two additional cars contained benzene, a chemical used in production of styrene monomer and other plastics feedstocks. The list said the two benzene cars were damaged by fire but were not breached.

East Palestine has a population of about 5,000. It is located 15 miles south of Youngstown and about 50 miles northwest of Pittsburgh.